There stands in Grosvenor Square an anachronism from the days when you would see Bobbies on the beat, an age without mobile phones, police walkie-talkies or when very few homes even had a landline telephone.

Despite the 24-hour armed police presence this blue police call box just north-east from the American Embassy in Grosvenor Square is available for public use. The door has not been sealed and behind it is a relatively modern telephone. Apparently, because of its sensitive location outside the US embassy, the post is still operational; just try using it if you dare. It still has its original notice stating that advice and assistance is obtainable immediately should you so need it. English Heritage have regarded its importance in the fabric of our lives highly enough to give it Grade II listing.

[F]irst introduced into Britain in the 1920s these police boxes were used by constables to keep in touch with the police station, they served to decentralise the police force allowing the officer to stay out without the necessity of returning to base for orders.

In 1929 the larger well-known police box made famous thanks to the BBC’s Doctor Who was introduced made of concrete at a cost of £43 each and by 1937 London had around 700 boxes installed. In true Tardis tradition there really was more to its inside than was apparent from the outside: phone, desk, chair, log book, first aid kit, fire extinguisher, electric heater and no doubt a kettle to make that well deserved cuppa. In an emergency they could be used as a prison for apprehending suspects and during World War II using a siren installed doubled up as an air raid warning system.

Very few police boxes have survived in London, apart from at Grosvenor Square they are located on the Victoria Embankment (opposite Middle Temple Lane), at the corner of Queen Victoria and Friday Street, on Walbrook (opposite Bucklersbury), in Guildhall Yard, outside St. Botolph Church in Aldgate, outside Liverpool Street Station, on Aldersgate Street near Little Britain, and on Piccadilly Circus at the junction with Piccadilly.

Most will only associate the police call box from the BBC’s Doctor Who programmes. The original Tardis (an acronym for Time, And Relative Dimensions In Space) used in the pilot episode had been constructed in the late 1950s for the long running series Dixon of Dock Green, which ran from 1955 to 1976 and became the longest running police drama to appear on television.

The pilot for Doctor Who was filmed at in London at the BBC’s Lime Grove Studios, but the box proved difficult to transport in the studio’s lift. When the first series was commissioned new Tardis was constructed 8 inches shorter from wood painted with the addition of Artex to simulate concrete. The other modification was that the doors crucially opened inwards.

The word Tardis became an official word in the English language with an entry in the 2002 edition of the Oxford English Dictionary.

In 1996, a brand new police box appeared on Earl’s Court Road, outside the tube station. In keeping with the Metropolitan Police’s obsession with surveillance, it was fitted with a CCTV camera, allegedly to scare off prank callers. Unveiled as part of the Metropolitan Police’s plans to reintroduce police boxes to the streets of London, plans to erect similar boxes throughout London have now been abandoned.

On the 1st July 1996 with the return of Doctor Who to the small screen the BBC filed an application to register the “Police Public Call Box” in relation to games, toys and playthings . . . the Metropolitan Police filed an opposition and the more cynical might construe that this new police box outside Earls Court as the Metropolitan Police asserting their right to the police box design.

All you need to know – and a lot more besides – about the Police Telephone Box can be found on Immanuel Burton and Jason Shron’s excellent website Police Boxes.