Jo Grant

Josephine Grant (later Josephine Jones), known simply as Jo, was placed in UNIT, against the Brigadier's wishes, by her uncle - General Hobson, a high-ranking official in the United Nations. The Brigadier decided that Jo could replace Liz Shaw, who had returned to Cambridge, as the Doctor's research assistant. Secretly hoping that the Doctor's attitude would put Jo off UNIT, the Brigadier told the Doctor that Jo would be an admirable assistant.

Early life
Jo had taken a A-Level in Science, but did not pass (DW: Terror of the Autons)

Life with the Doctor
Jo's first meeting with the Doctor didn't bode well for the future, as she mistook an important experiment for an accidental fire. She ruined it by dousing it with a fire extinguisher, which earned her the Doctor's wrath. Despite this initial clumsiness, her failures fueled her enthusiasm, and she became more determined to prove people wrong about her. When, for example, she recovered from the Master's hypnosis, she disobeyed orders and followed the Doctor to Rossini's Circus. There, she proved her competence by rescuing the Doctor. Having been hypnotised by the Master once, Jo was able to resist his hypnosis on further encounters by reciting nursery rhymes (DW: Frontier in Space). One such time, she reacted to the hypno-sound by seeing a Drashig, a Mutant and a Sea Devil.

Jo claimed to be a qualified agent, but she may have exaggerated about this, in the same way she exaggerated the extent of her A-Levels. After saying she took an A-Level in Science, she later revealed that "I didn't say I passed." That said, there can be no doubt of Jo's escapology abilities. She could ride a motorbike, use karate, pick locks, abseil, and even pilot a helicopter - all of which came in very useful during her time as the Doctor's assistant. These abilities combined with her enthusiasm proved Jo to be an asset to UNIT.

Jo did not initially believe the Doctor when he said he was a time traveller. For a substantial period of her time with him, she thought his tinkering with bits of TARDIS was pointless. In fact, she may have been with the Doctor for as much as a year before she even stepped foot into the TARDIS. When she finally did, the Doctor discovered that Jo was not a particularly natural time traveller. In contrast with modern companions like Martha and Rose, she was extremely tentative during her first trip away from Earth. She repeatedly begged to be taken back home, before she realized that the Doctor had little ability to grant her wish. After the Doctor coaxed her, she did eventually step out of the TARDIS and into her first adventure on another world. (DW: Colony in Space) Jo's initial timorousness was eventually replaced by a more matter-of-fact approach to space travel.

On one particular evening Jo was dressed up ready for a night on the town with Captain Mike Yates, which proved to be fortunate as she and the Doctor landed on the planet of Peladon. The Doctor was mistaken for the Earth chairman of the committee assessing Peladon's application to join the Galactic Federation. Jo was introduced as an Earth Princess, as she was dressed in an appropriate manner - and only those of Royal blood were allowed to enter the conference chamber. King Peladon was smitten, and later proposed marriage, but Jo wasn't impressed. Over the time she and the Doctor were on Peladon, Jo did grow to like the King, but decided that she really must return to her own planet.

Once the Doctor regained his knowledge of time travel, Jo was persuaded to take a short trip in the TARDIS, and she subsequently took many more trips with little persuasion.

Jo learnt well with the Doctor, and when he was unwilling to complete the Time Ram, it was she who finished the action. She realised why the Doctor was reluctant, but saw the potential outcome of not completing it. (DW: The Time Monster)

Whilst Jo was certainly a member of the team, her individualism made her stand out in UNIT, and her desire to follow her own instincts and speak her mind brought her and the Doctor close. They were both very different from the norm in UNIT. Nearing the end of her time with UNIT, Jo told the Brigadier that she was going to Llanfairfach even if it meant resigning. Ironically he had orders for her to go there anyway, so her threats were unnecessary. (DW: The Green Death)

Departure
Once Jo arrived in Llanfairfach, she met Professor Clifford Jones. She was already aware of him, having read reports of his work, and ideals, in various newspapers. Jo already admired Cliff before she met him, and as she was telling the Doctor about him she said that he reminded her of a younger version of the Doctor. Over the short time that UNIT were in Llanfairfach, Jo and Cliff fell in love. Jo agreed to marry him, and left UNIT. This came as something of a disappointment to Mike Yates, who had always hoped to be involved romantically with Jo himself. Despite his sadness, Mike did attend Jo and Cliff's celebration party, and put on a brave face. The Doctor, on the other hand, was devastated, drank his champagne in one, and left on his own, after giving Jo a blue crystal from Metebelis III. Before Jo and Cliff left for the Amazon (for what could be described as both a research trip and their honeymoon), she asked her uncle to get UN status for the Wholeweal community. (DW: The Green Death)

Later life
A few months later, the couple, who were already on their trip up the Amazon River returned the crystal to the Doctor via mail, as they felt it was bringing them bad luck. (DW: Planet of the Spiders) There are two conflicting accounts of the Jones's life after their last contact with the Doctor - one states that they had a son named Matthew and became estranged from one another by the 1990s (EDA: Genocide), another presented them as still happily married as of the late 2000s. (BFA: The Doll of Death)

In 2010, Jo met Sarah Jane Smith, another former companion of The Doctor, while investigating the Shansheeth and the Doctor's death.