Police box

A police box — or police public call box — was a telephone kiosk that could be used by the police to call into a station (TV: Logopolis) or by members of the public wishing to get help from the police. (TV: "Bell of Doom")

Unlike telephone booths, a police box phone was on the outside of the structure, in a little compartment that had an exterior, instructional label. (TV: The Empty Child) According to Tegan Jovanka, who once read aloud the instructions on a TARDIS disguised as a police box in the Borough of Barnet, the instructions were:
 * Police Telephone
 * Free for Use of Public
 * Advice and Assistance Obtainable Immediately
 * Officers and Cars Respond to Urgent Calls
 * Pull to Open (TV: Logopolis)

Function and physical characteristics
Police boxes were about the size of a large cupboard, and could provide shelter to those police officers who had the key. Inside were kept a writing desk and stool, as well as materials relevant to the conduct of police business — such as clipboards, writing utensils and forms.

As the Ninth Doctor once pointed out, there was enough space in a typical police box to temporarily house a prisoner. He indicated that a typical usage was for a policeman to pop an arrested individual into the police box and lock the doors until transport to a station could be arranged. (TV: Boom Town)

Real life incidents and appearances
In the time before telephones and modern policing, a culture of art and prophecy developed around "the blue box", appearing in religious stained glass windows, (TV: The End of Time) paintings, (TV: The Pandorica Opens) and ancient prophecy. (TV: The Fires of Pompeii) This lead to the inspiration of the design of the police box as a place one could find help. (COMIC: Prisoners of Time, Hunters of the Burning Stone)

On 11 June 1925, a police officer at first mistook the Fifth Doctor's TARDIS for a real police box until invited inside by him. (TV: Black Orchid) The Eleventh Doctor mistook a real police box for the TARDIS on Christmas Eve 1938. (TV: The Doctor, the Widow and the Wardrobe)

In Foxgrove on 18 August 1951, Sarah Jane and Luke stumbled upon a police box. They thought that the Doctor had arrived to help them, but realised it was an ordinary police box when PC Ferguson popped his head out. (TV: The Temptation of Sarah Jane Smith)

In Wales in 1959, American secret agents Jerome Weismuller and Hawk used a police box to contact their superiors at the Pentagon. (TV: Delta and the Bannermen)

An actual police box sat across the street from where the Seventh Doctor had landed the TARDIS in 1963. (TV: Remembrance of the Daleks)

Returned to London in 1965, Ian Chesterton and Barbara Wright amused themselves after sighting a real police box. (TV: The Chase) During a trip to London in 1966, the Ninth Doctor appreciated the fact that it was one of the rare occasions the TARDIS' police box exterior was "any cop as a disguise". Rose Tyler noticed the TARDIS had landed next to a genuine police box and asked if they normally came in pairs. (COMIC: The Love Invasion)

The Doctor's TARDIS materialised around the Barnet Bypass police box, whereupon Tegan Jovanka entered the Doctor's TARDIS shortly thereafter, mistaking it for the genuine police box. Later, the TARDIS dematerialised, leaving the nearby policemen with the normal police box. (TV: Logopolis)

The Barnet Bypass police box was mistaken for the Doctor's TARDIS by Prince Genei, who immediately abandoned his plans to conquer Earth. Shortly afterwards, the police box — the last of its kind in England — was taken away, as it was considered useless. (PROSE: Useless Things)

In 2006, Bridget Sinclair showed LINDA slides of the Doctor's TARDIS, which she described as looking like "a faux police box". In fact, she only had photos of various real police boxes. (TV: Love & Monsters)

Attempting to feign ignorance as regards the TARDIS, DI Patricia Menzies told the Sixth Doctor in 2010 that she thought that they only had police boxes in Scotland. (AUDIO: The Crimes of Thomas Brewster)

Polly Wright told Thomas Brewster that she hoped that the Doctor had returned for her every time that she saw a police box. (AUDIO: The Three Companions)

When Alexei found the TARDIS on London's South Bank, Mahler mentioned an embarrassment on Earl's Court, implying that they'd earlier attempted to raid the actual police box stationed there. (TV: The Bells of Saint John)

On her first sight of the TARDIS, Yasmin Khan compared the ship to a green police box on Surrey Street, Sheffield. (TV: The Ghost Monument)

The Doctor's TARDIS
On multiple occasions, ships, mainly TARDISes, had taken the shape of actual police boxes.

DI Billy Shipton was familiar enough with real police boxes to recognise the TARDIS as a counterfeit in 2007. (TV: Blink)

Upon de-cloaking the TARDIS in the Oval Office in 1969, the Eleventh Doctor claimed that he and his companions were from Scotland Yard. (TV: The Impossible Astronaut)

Early in the First Doctor's travels, the TARDIS assumed the exterior shape of a police box during a stopover in 1963 London. Due to a malfunction in its chameleon circuit, the TARDIS became locked into that shape. (TV: "The Cave of Skulls", Boom Town, Utopia) The Eleventh Doctor had in fact purposefully destroyed the chameleon circuit, to inspire the look of the police boxes by spreading it through human history and culture. (COMIC: Hunters of the Burning Stone)

Dodo Chaplet entered the TARDIS believing it to be a police box and wanting to make an emergency call about a road accident. (TV: The Massacre of St Bartholomew's Eve)

On a visit to London in July 1966, the Doctor solved the potential problem of local policemen mistaking the TARDIS for a genuine police box and trying to use it, by hanging an "OUT OF ORDER" sign on its doors. However, Dodo did point out to him that not even the police would be able to open the door. (TV: The War Machines)

Bill theorised that the Doctor deliberately kept the TARDIS' disguised as a police box due to the implications behind the "Advice and Assistance Obtainable Immediately" line on its door. (TV: Smile)

Other ships
On 28 February 1981, as part of a complex plot,  materialised his TARDIS around a real police box on the Barnet Bypass. The Doctor's TARDIS, still disguised as a police box, materialised around the Master's TARDIS, also disguised as a police box, creating a dimensional anomaly and a trap for the Doctor. (TV: Logopolis)

The Doctor manipulated the chameleon circuit of the Monk's TARDIS to make it assume several shapes, including that of a police box. (TV: The Daleks' Master Plan)

When the Doctor once more met the Monk, he had voluntarily configured his TARDIS into the shape of a police box. (COMIC: 4-Dimensional Vistas)

Behind the scenes

 * The British Broadcasting Corporation holds a trademark to the British design of the police box as used on Doctor Who.
 * Although the TARDIS is depicted and referred to as resembling a wooden box on a number of occasions in the series, the exact design of police box the TARDIS is based on was built of concrete. Earlier models were indeed made of wood.
 * The production team planned to feature the Barnet Bypass box in the series in Logopolis, only to discover that it had been vandalised shortly before the filming dates. The series' spare police box prop was refurbished and pressed into service to stand in for the actual box.