Petronella Osgood

Dr. Petronella Osgood (PhD) was a scientist who worked for UNIT, acting as the Scientific advisor to Kate Stewart, in the early 21st century. (AUDIO: The Sacrifice of Jo Grant)

An admirer of the Doctor, she eventually met the Time Lord during the infiltration of UNIT by Zygon invaders, which was resolved by the Eleventh Doctor joined by his tenth and war incarnations. (TV: The Day of the Doctor)

The original Osgood and her Zygon double became indistinguishable from each other to everyone else. They refused to identify which one of them was Zygon and which was human. (TV: The Zygon Invasion) Her Zygon double was later killed by, (TV: Death in Heaven; AUDIO: Narcissus; WC: The Zygon Isolation) but after a Zygon rebellion was ended peacefully, the Zygon rebel leader Bonnie took her place by assuming the form of Osgood to maintain the peace. Both Osgoods still refused to identify whether she was the human or Zygon version, but promised to identify as human or Zygon one day when no one would care anymore. (TV: The Zygon Inversion)

Early life
Petronella Osgood (TV: The Zygon Inversion) was the daughter of Frank Osgood and sister of Nova, (PROSE: For the Girl Who Has Everything) of whom she was jealous. (TV: The Day of the Doctor) She was born into a family of science geeks (AUDIO: Earthfall) and had family connections with UNIT, (AUDIO: Power Cell) being related to someone whom she expected John Benton would know. (AUDIO: Call to Arms)

When Osgood was young, she was part of a chess club. (AUDIO: Vanguard) She went on to study at King Henry's University in London, where she befriended Jay Roy. (AUDIO: Power Cell) She achieved at least one PhD (AUDIO: The Sacrifice of Jo Grant) and was employed by the Ministry of Defence at Dstl where she was mentored by Professor John Torrance. (AUDIO: The Sontaran Project)

Working for UNIT
Osgood was recruited into UNIT in November 2011, (PROSE: For the Girl Who Has Everything) because of family connections, (AUDIO: Power Cell) via a relative she assumed John Benton would have met. (AUDIO: Call to Arms)

Osgood enjoyed reading files on the Doctor's exploits, and idealised several of the Doctor's companions. (AUDIO: Call to Arms, Tidal Wave) At some point, she met Sarah Jane Smith. (PROSE: The Day of the Doctor)

Preventing a Nestene invasion
Osgood often created pieces of technology to aid in UNIT's missions, typically to stop the soldiers from shooting at aliens, much to Kate Stewart's delight. She tracked a set of energy units falling to Earth and warned Vikram Shindi about it. (AUDIO: Vanguard)

Together with Lieutenant Sam Bishop, she was deployed to the Gobi Desert in Mongolia in search of a Nestene energy unit. She had created a holographic image projector from alien technology. (AUDIO: Earthfall)

She tried to examine the energy unit using all the techniques she could think of. Kate also told her to examine one of the 3D printers. When the Nestene escaped the energy unit, she discovered that the Nestene could combine through the internet. (AUDIO: Bridgehead)

She created a new weapon to destroy the Autons and was able to free Captain Josh Carter from Nestene control. (AUDIO: Armageddon)

Tengobushi incident
After going to a pub quiz with Jay Roy, she was tasked with working out which pieces of UNIT property Lyme Industries had managed to get their hands on. She later asked Jay to help her in her work in order to work out what was kidnapping people. She started to show Jay the ropes but didn't get too far when a Tengobushi attacked. Jay decided to protect her and detonated a bomb in her flat killing himself in the process. (AUDIO: Power Cell)

Osgood went to Geneva and decided to visit local Galleries, where she was followed and attacked by Dokan. She later went with Kate and Grant Avary to investigate a set of murders on a French mountainside. She returned to Geneva to analyse some secretions and was attacked by the Tengobushi but was save by Josh. She realised that the Tengobushi wanted her for her knowledge of an alien artefact and used this to get into their ship. (AUDIO: Death in Geneva)

Osgood and Kate had to fly their plane after the Tengobushi killed the pilots during their flight. She then investigated the Kamishi energy cell in the surroundings of the Black Archive. As part of her experiments, she accidentally released some power that caused some earth tremors. After the Tengobushi released an energy barrier around the Tower of London, she released the ravens to observe their advance. During the attack, Osgood was trapped in the Archive until Josh helped get her first to the Jewellery room and then to command centre. She managed to work out how to use the energy cell and weaponised it to aid their escape. (AUDIO: The Battle of the Tower)

When they were under lock and key in UNIT's base under the Rock of Gibraltar, Osgood managed to hack into the base's computer to get their release. Whilst at Lyme's base in Antarctica she worked out a way to destroy the generator and destroyed it with the help of Dokan, who questioned her about her actions. (AUDIO: Ice Station Alpha)

Investigating the Silence
Osgood received a panicked call from Colonel Shindi who detected something near Helena Faversham's residence. While she was tracking the Silents, she kept forgetting the positive readings, and after she was attacked by the Silents, she soon forgot. She then questioned Faversham using a truth serum. (AUDIO: House of Silents)

Osgood worked on a universal translator which could understand Axons and Sontarans. She helped Bishop investigate what happened at the Faversham estate and later worked out a simplistic way of remembering the Silents: by writing stuff down. Investigating the people that went to Faversham's home, she started with the ones closest to her but they all disappeared. She and Bishop tracked Derek Butler but he was snatched from under her nose. She then looked through all the videos the people she was looking for had made and found subliminal messages to get the UK population to trust Kenneth LeBlanc. (AUDIO: Square One)

A month later, she had to brief the rest of UNIT about her solution to getting the rest to remember the Silents. She had created a pair of sunglasses which had 360-degree cameras which could give them all views of the Silents. She called the Silents "Edvard". After she stole Carter's laptop, using the same techniques the Silents used, she found a large order of guns and explosives he had ordered. She discovered from Heston where he had taken the things Josh ordered. She then tried to convince Josh not to kill LeBlanc but couldn't, so she knocked him out. (AUDIO: Silent Majority)

Osgood went with Bishop to the UNIT satellite to fix something there, but they were knocked unconscious upon arrival. Later, she started to explore the space station and found a Silent on-board. She discovered that the crew were being controlled by the Silents and had exposed the spy satellites of all the governments of the world. She tried to get the Telokni ship to stop shooting them, but couldn't and had to escape. (AUDIO: In Memory Alone)

The Silurian invasion
Osgood was investigating a Silurian nest near Scafell when they started to attack. She managed to escape to John Benton's pub. She tried to contact UNIT HQ but barely got a message through to Josh. Noticing that the Silurians retreated when Terry Waring's car blew up, she devised a plan to burn the beer cellar of the pub and create a backdraft to halt the Silurians' progress. She then escaped in Bessie. (AUDIO: Call to Arms)

She was sent with Jo Jones to investigate "Project Charybdis". She donned her own version of the Third Doctor's velvet outfit. Whilst there, the project was hijacked by Anthony Burmaster to get to a Sea Devil base. She managed to escape before the Project exploded. When Jo decided that she should continue the Doctor's work, Osgood got her to the Sea Devil base. She later stopped Kate from destroying the Sea Devil base by noticing that the tremor wasn't a weapon but the base collapsing. (AUDIO: Tidal Wave)

Osgood went with Kate to a Silurian nest in Greece, where she met some dormant dinosaurs. She was looking for a device to control Krellix's hybrids. Tryska used a machine that induced fear into her, and she relived race memories of the Silurians and started to run around the base. Sam later found her covered in a liquid and regressed to a primitive state. But in that state she found a way to stop Tryska before the base blew up. (AUDIO: Retrieval)

She realised that the Silurians must have been breeding dinosaurs in a breeding programme for millennia. Managing to get to London, she got to her lab to find a way of disarming the Silurians without killing them. Jo started to help her in the work. She eventually found a possible solution for stopping the dinosaurs the Silurians rode. She was able to disarm the nuclear weapons that Kalana had armed. After the defeat, she went with Jo and Sam to South America in order to return the sea creatures back to the Sea Devil base. (AUDIO: United)

Investigating the Auctioneers
She and the team flew to South America on intelligence that a local resistance force had obtained alien technology. There they met resistance leader Captain Maria Gonsalves and discovered she had a captured Dalek in her secure bunker. While Kate and Shindi searched the jungle for possible other Daleks, Osgood and Josh searched the base. They discovered a series of rooms containing human weapons augmented by alien technology and were captured by Gonsalves. Held captive with Kate in the bunker, they both discovered Gonsalves was part of a worldwide auction house of alien technology and weapons. Having re-entered its casing, the Dalek killed Gonsalves and self-destructed, destroying the bunker. Having escaped the explosion, Osgood and the team were then rescued by the American arm of UNIT. (AUDIO: The Dalek Transaction)

Working late in her lab on Halloween, Osgood picked up a broadcast from an obsolete satellite called Voxtel, partially broadcasting in Latin. When Josh arrived back from a party saying he saw an apparition of a Grey Man at the same time as the broadcast, Osgood believed the two were connected in some way. After hearing some unsettling messages from Kate, Josh persuaded Osgood to accompany him up to Ealdon House in a UNIT helicopter. Once there, Osgood discovered the apparitions of the Grey Man were created by a particular resonance in the house, causing fear in humans. Alice Donelly had also discovered this resonance in the house years before and she wanted to harness it as a weapon before Kate’s father stopped her. Now with apparitions of the Grey Man appearing across London and an unknown alien presence drawing near, responding to the Voxtel message Alice left years ago, Osgood and Kate deciphered and completed the message, averting the crisis. (AUDIO: Invocation)

After attending the New Science Conference, Osgood ran into an old mentor of hers; Professor John Torrance. He persuaded her to let him give her a lift home, or close to, but he ended up taking her to his workplace, the Torrance Research Foundation. There, Osgood discovered Torrence and his colleague Christine Colley had been engaging in cloning research, and was introduced to Max, a cloned Rhesus Macaque. She also discovered a captured Sontaran called Merx who had been experimented on so Torrence could clone a Sontaran army via his own methods. This army would then be sold off through Colley’s contacts in the worldwide auction. Confined together, Osgood and Merx hatched a plan to escape, but were rescued by a combined force of Sontarans and UNIT. With the cloning project and the Foundation being shut down, Osgood took Max to safety. (AUDIO: The Sontaran Project)

Osgood and Josh became trapped in a sideways dimension after an experimental travel capsule took them there by mistake. Here, UNIT was run by a fascist state with different versions of the team, including herself. She was startled to discover this world’s Osgood and Josh were very much an item, and she had some trouble avoiding his advances. Unfortunately, Josh was forced to leave with the evil Osgood, but the capsule left behind a dimensional tear that non-evil Osgood used as a gateway to jump across to her own reality. When she returned, Josh, without thinking, planted a large kiss on her lips before realising his mistake. Soon the other Osgood attempted to escape again in the capsule. With its power levels approaching critical, Osgood managed to persuade her other self to jump start the capsule just before the dimensional gateway imploded. (AUDIO: False Negative)

Osgood went with Kate to find Bishop in an auctioneers base. The Overseer gave her a pair of virtual reality goggles which held instructions for both of them to follow. This led them to a site outside Bristol. She had to solve puzzles in the virtual world to stop bombs in the real world. She worked out that they didn't need to race around the UK, they needed to be at the Auctioneer's warehouse. She found Bishop in a box in the centre of London. She thought that the VR technology came from a parallel world. (AUDIO: Game Theory)

On examining the VR equipment, Osgood realised it was a bridge to another universe. She, Carter and Shindi experimented in the virtual world. She thought that it was amazing that they could actually interact with the parallel world. In this world, they were attacked by mutated dogs and then by metal worms. Osgood observed that the dogs had been converted and realised that the world could be affected by their imagination. She became concerned when they realised they were on a parallel Earth. She thought that there was something familiar about the hive she saw in the virtual world. She started to be cyber-converted. (AUDIO: Telepresence)

Osgood was connected to the cyber-network. She stopped the Cybermen from fully converting Bishop and Shindi. She told the Cybermen that the reason she wasn't fully converted was because they were using emotional responses. She tried to work out what they were doing and told them that she could get the whole Earth under control within a matter on minutes. She planned to use the Auctioneer app to use this. She got the Cybermen to find Kate in order for her to reverse the communications blackout. Using her improved hacking skills, she undid Kate's communications shield and sent the app to everyone on Earth. (AUDIO: Code Silver)

Osgood realised that was in the UNIT base and updated the Cybermen on him as well as getting her gun that might stop him. She asked the Cybermen to convert the Master. She sent Shindi and Bishop after Kate, the Master and Carter. She again had to remind the Cybermen not to convert her, and showed them her usefulness by changing a conversion unit to work on a Time Lord. She placed the Master in the conversion chamber. Shortly afterwards she was uncoverted. She was used by the Master as a hostage so that he could escape. Later, she rewrote the app again to uncovert the humans. (AUDIO: Master of Worlds)

Revisiting old threats
Kate told Osgood to deliver what the Master had found in the Auctioneer's vault to the Well. She later interviewed Shana Siddiqui for a position. During her time in a decontamination suit, she wore a stick of celery. She asked Shana to help her study a Wirrn. After the Wirrn escaped, she discovered that Shana had been infected and planned to study the infection. She tried to get Shana to resist the infection. She used the Ravens to attack the Wirrn. After discovering that it was an ancient virus that killed the Wirrn, she injected Shana with one from the Archive. (AUDIO: Hosts of the Wirrn)

Whilst undertaking an experiment, Osgood was interrupted firstly by Josh and then by a capsule coming to the Tower. She worked on trying to translate the language of the creatures. She later explored the Black Archive for a weapon Vara had told her about. She wasn't happy that Kate was going to hand over the aliens to her people, and thought it wasn't fair. She supplied Vara with the weapon. (AUDIO: Breach of Trust)

She joined Kate on an investigation to the Pandora Institute. Whilst there, she experienced a nightmare where she was useless to stop an invasion. She managed to get back her communications device and contacted Shindi. She later told Josh of this, and they realised that they had both heard the same noise. She worked out that Seth Hyer projected the fears of the patients which made some of them die. She got Shindi to send a platoon to the island as there was an alien incursion. She then reconfigured her holograms to reflect Seth's own image which destroyed it. (AUDIO: Open the Box)

Alien incursions
Kate took Osgood and Josh to Abbey Marston in order to resurrect Warren Calder and find out where he hid the Silurian plague that he claimed to have stolen shortly before ending his own life. This was revealed to be a ruse by Calder who wanted Kate to resurrect him in Abbey Marston so that he could use the stone circle to steal a new body and cheat a terminal illness that he had been diagnosed with. However, in doing this, he released the Static, who planned on stealing bodies of their own so that they could exist on Earth. They were defeated by Kate, Osgood, Josh and Calder when they destroyed the stone circle. (AUDIO: This Sleep of Death)

Osgood and Sam Bishop investigated unusual weather conditions revealed to have been caused by the Animoi. (AUDIO: Tempest)

Osgood investigated her own murder when her body was discovered within a power station. She was suspicious of the director, known as "River Song". However the director was in fact a Wampeerix Battle Queen masquerading as River Song, intent on feeding off the energy of the Earth. The real River Song aided Kate and Osgood in defeating the Wampeerix. (AUDIO: The Power of River Song)

Meeting the Doctor
Osgood was present when the TARDIS, with the Eleventh Doctor and Clara Oswald inside, were brought to the National Gallery in an effort to understand what had happened to several paintings in the Under Gallery. The Doctor took a liking to her long multi-coloured scarf, which was strikingly similar to one he wore in his fourth incarnation. She displayed a type of hero-worship belief in the Doctor, twice "praying" to him to save her during moments of danger.

On the Doctor's orders, she and fellow scientist McGillop analysed the stone dust in the Under Gallery and eventually realised that the dust on the floor was the remains of the statues, which had been smashed by Zygons that had escaped from the paintings in order to hide. She was cornered by a Zygon, who took her form. The Zygon disliked the fact that Osgood was asthmatic, and, annoyed at "getting one with a defect", promptly took her inhaler. Osgood escaped by tripping the Zygon with her scarf, and reclaimed her inhaler.

She made her way to the Black Archive, and was present along side her Zygon-double when Kate threatened to destroy London, rather than let the alien technology in the archive fall into Zygon hands. Like the other humans and Zygons in the room, her memory was temporarily cleared by three incarnations of the Doctor, so that she could not recall whether she was the real Osgood or her Zygon duplicate. As peace talks ensued, she realised who the real Osgood was when the Zygon duplicate began wheezing and did not have the inhaler. She gave it to the Zygon, and both Osgoods agreed to keep their discovery a secret so as not to disrupt the peace talks. (TV: The Day of the Doctor)

Operation Double
The two Osgoods created Operation Double, where a group of 20 million Zygons would be allowed to live on Earth and take on the form of the nearest person they could find. The treaty could only be maintained if both humans and Zygons agreed to live among each other in peace, and that no harm would come to anyone. They were given a device called the Osgood Box by the Doctor, only to be used only in a dire emergency. (TV: The Zygon Invasion)

In 2014, one of the Osgoods was sent to Bonnybridge to investigate another U.F.O. sighting in the area. Because of this, she missed the first known interaction between the Twelfth Doctor and UNIT as well as the Fractures' attack on London. (COMIC: The Fractures)

After her Zygon double was killed by, (TV: Death in Heaven; AUDIO: Narcissus; WC: The Zygon Isolation) Osgood refused to state whether she was the Zygon or the human in order to maintain the treaty. She became a target of a revolt from a rogue group of Zygons who believed they had been betrayed. (TV: The Zygon Invasion)

After the Doctor convinced Bonnie, the leader of the Zygon revolt, to stop her plan, Bonnie also assumed Osgood's form and acted as the second protector of Earth alongside the other surviving Osgood. She felt that they were a credit to both humans and Zygons and planned to take on the role of protecting the Earth from threats. (TV: The Zygon Inversion)

The Osgoods created a series of files documenting alien species and foes encountered by the Twelfth Doctor beginning with the Zygons and their involvement in Truth or Consequences. Other files documented King Hydroflax, the Mire, The Veil and the Sandmen. (PROSE: The Osgood Files)

In September 2015, the two Osgoods watched prime minister Daniel Claremont's speech on global warming at Ravenscaur School with Kate Stewart in the Tower of London. After Claremont was revealed to be a Sea Devil during the speech, the Osgoods recommended that Kate call the Doctor. The Twelfth Doctor was already there and he defeated the Sea Devils without UNIT. (COMIC: Clara Oswald and the School of Death)

In early 2016, one of the Osgoods was in London when it was attacked by K2. She called the Twelfth Doctor and he took her into his TARDIS. They materialised above the London Eye as it was attacked by the robot. The Doctor used his sonic screwdriver to destroy K2, but he fell out of the TARDIS. Osgood saved him by throwing her scarf out of the TARDIS for the Doctor to catch. (COMIC: Robo Rampage)

On the eighth of March of an undisclosed year, Bonnie and Petronella struggled to work together at the UNIT lab until they discovered that Josh Carter had mysteriously disappeared the night before.

Together, they decided to investigate the Narcissus dating website and find Josh. Bonnie took the form of Jacqui McGee using her Narcissus profile and met with Jordan Love, who appeared as someone she knew during her reproductive days. However, Jordan soon discovered that she was an imposter and attacked her with a burst of energy that would’ve killed a human, but being a Zygon, she was able to survive albeit injured.

Meanwhile, Petronella prepared to confront Jordan Love on their spaceship. Bonnie tried to stop her, believing that she was more disposable than her sister. Petronella went ahead with the mission anyway and unwittingly defeated Jordan due to her complete self-reliance and contentment being toxic to them. Josh was rescued and returned to UNIT. Following these events, Bonnie and Petronella reconciled, agreeing that two Osgoods are better than one. (AUDIO: Narcissus)

One of the Osgoods was picked up from UNIT HQ by the Twelfth Doctor while the other had gone out to pick up some coffee. The Doctor took this Osgood on her first trip in the TARDIS and asked her to prepare a briefing for him after they arrived on Nayspiel, the capitol mega-city of the Alliance. They stopped a plot by the Lisban corporation to invade the planet Albensi. The Doctor returned Osgood to UNIT HQ just in time to see the return of her sister. (AUDIO: Field Trip)

In October 2016, one Osgood mailed the other based on a large increase of transmitter activity coming from Saxon Heights. They realised that this was Missy and later had UNIT crash into the school. However Osgood later confirmed to Kate Stewart that they had lost her. (PROSE: Yes, Missy)

One of the Osgoods was the commanding force behind UNIT's shutting down of Harmony Shoal, following an anonymous tip off. (TV: The Return of Doctor Mysterio)

The Doctor invited her on a trip in the TARDIS to a planet who were in the midst of planning an invasion. Osgood witnessed the debate and had some suggestions to improve policy. A couple of people tried to stop the proceedings and the Doctor asked her to chase after one of them. She was eventually caught and interrogated by one of them and discovered that the assailant was trying to stop the invasion. Osgood was then placed undercover to help the Doctor plant a virus in a private company's servers. She used one of her gizmos to jam the signals to help the Doctor talk to the invaders. (AUDIO: Field Trip)

When Jenny's bowship crashed into the Terrance Dicks Library, one of the Osgoods examined the craft only to wind up infected with the white energy from the Void. Spreading the infection to the other UNIT troops, she was slaved to the will of a rogue Type 1 TARDIS before the Doctor managed to have the Type 1 stand out. (COMIC: The Lost Dimension)

After UNIT's closure
On 10 May, 2020, at around 18:30 pm, Osgood and her Zygon duplicate watched The Zygon Invasion, an episode from the ninth series of Doctor Who. (WC: The Zygon Isolation)

Personality
Osgood was a "fan" of the Doctor and knew of many of his previous incarnations. She would pick iconic items (i.e. multi-coloured scarf, bow tie) from the incarnations she knew of and wore them herself. (TV: The Zygon Inversion) When asked by the Twelfth Doctor if she would like to travel with him, she was so excited that she had to use her inhaler. (TV: Death in Heaven) Osgood would become saddened if she learned she missed a chance to see the Doctor; one of her fellow scientists even stated she would be disheartened to learn the Doctor had regenerated again after she had just started mimicking his previous self's fashion. (COMIC: The Fractures)

Osgood was very intelligent. She alone was able to work out the reason why the Zygons smashed the statues in the Under Gallery. (TV: The Day of the Doctor) She also surprised the Twelfth Doctor by correctly presuming that Missy was the Master regenerated into female form: UNIT kept files on all past Prime Ministers, including the Master. (TV: Death in Heaven) She also came up with a hypothetical plan for invading Earth by killing the Doctor by shooting him between the eyes for each regeneration, never allowing him to talk. (TV: The Zygon Inversion)

She managed to figure out whether she or her Zygon doppelganger was the real Osgood after the Tenth and Eleventh Doctors, joined by the War Doctor, jumbled their minds, making them unable to determine their own species, in an attempt to facilitate negotiation of the ultimate peace treaty. She discovered this when her Zygon counterpart suffered an asthma attack, motivating her to pass her asthma inhaler to the other Osgood. (TV: The Day of the Doctor)

Osgood had a sister to whom she negatively compared herself. (TV: The Day of the Doctor) Missy observed that she had little confidence in herself. Osgood was able to keep her cool, even when faced with the threat of death from Missy and tried to reason her way out. (TV: Death in Heaven)

Appearance
Osgood dressed according to the Doctor's fashion senses from various incarnations, choosing to wear a similar scarf to that worn by the Fourth Doctor. (TV: The Day of the Doctor, COMIC: Robo Rampage) She also wore an olive green moleskin overcoat and a burgundy bow-tie similar to those worn by the Eleventh Doctor. (AUDIO: Tidal Wave) She also wore a shirt with question marks on the collars, like the Fourth, Fifth and Sixth Doctors. When the Nightmare scenario occurred she wore items of clothing similar to the Seventh Doctor when he visited Maiden's Point. (TV: The Zygon Invasion) On at least one occasion she wore a costume inspired by the Sixth Doctor. (COMIC: The Lost Dimension) When Kate sent Osgood on a mission with Jo Jones, she wore a velvet jacket and a frilly shirt like the Third Doctor. (AUDIO: Tidal Wave)

She had tattoos of the Doctor's various incarnations across her body, and wanted to add all of their faces eventually. (PROSE: The Day of the Doctor)

Behind the scenes

 * On 24 July 2014, Ingrid Oliver appeared in-character as Osgood in a video thanking fans for helping the official Doctor Who Twitter account reach one million followers.
 * Osgood appears as a background character in the London scene and the hidden Black Archives location in the Doctor Who level pack in LEGO Dimensions.

Family ties

 * In DWM 484, Steven Moffat admitted his intention when writing was for Osgood to be the daughter of UNIT soldier Tom Osgood from the Third Doctor era. However, he did not want to state this definitively in the script so fans would be able to form their own interpretations.
 * In the audio story Power Cell, Osgood responds to the suggestion that she had an uncle who used to run around shooting aliens with "something like that". This is consistent with the theory that Tom Osgood is Osgood's father and with the lack of definitive confirmation.
 * In the audio story Call to Arms, John Benton says Osgood is "just like him", and she automatically assumes he means someone specific other than the Doctor — "you mean, just like my..." — but her inquiry cut short before she names them.
 * In the short story For the Girl Who Has Everything, however, Osgood's father is named Frank, though this confirmation does not negate the possibility of Tom Osgood still being related to Petronella.