The red telephone box is a telephone kiosk for a public telephone designed by Sir Giles Gilbert Scott, the architect responsible for famous sites like Liverpool Cathedral and Battersea Power Station.

The telephone box is a familiar sight on the streets of the United Kingdom, its associated Crown Dependencies, the British Overseas Territories and Malta. Despite a reduction in their numbers in recent years, the traditional British red telephone kiosk can still be seen in many places throughout the UK, and in overseas territories, the Commonwealth and elsewhere around the world. The colour red was chosen to make them easy to spot.

From 1926 onwards, the fascias of the kiosks were emblazoned with a prominent crown, representing the British Government. The red phone box is often seen as a British cultural icon throughout the world. In 2006, the K2 telephone box was voted one of Britain's top 10 design icons, which included the Mini, Supermarine Spitfire, London tube map, World Wide Web, Concorde and the AEC Routemaster bus. In 2009, the K2 was selected by the Royal Mail for their "British Design Classics" commemorative postage stamp issue.

Many of the phone box designs are protected by trade mark registrations and copyright, held by British Telecommunications plc. In 2019, the prototype K2, located at Burlington House in London since 1924, was listed to Grade II* in "recognition of its iconic design status".

Design history

K1 The first standard public telephone kiosk introduced by the United Kingdom Post Office was produced in concrete in 1921 and was designated K1 (Kiosk No.1). The Post Office had taken over almost all of the country's telephone network in 1912. Some local authorities refused to give permission for the K1; Eastbourne Corporation insisted that the kiosks could only be installed if they had thatched roofs. The design of the K1 was not of the same family as the familiar red telephone boxes. As of 2021, there remain fourteen K1 boxes in the UK, including seven that are in museums and museum collections. A further two remain in the Republic of Ireland. Seven of the UK's fourteen have been listed at Grade II by Historic England, some of them still located on British streets, including one situated in Trinity Market in Kingston-upon-Hull, and another in Bembridge High Street, Isle of Wight. The kiosk is in fact outside the former optician's, now Captain Stan's Fish Shop, 5 High Street.

K2

The red telephone box was the result of a competition in 1924 to design a kiosk that would be acceptable to the London Metropolitan Boroughs which had hitherto resisted the Post Office's effort to erect K1 kiosks on their streets.Stamp 1989, pp. 4–7.

The Royal Fine Art Commission was instrumental in the choice of the British standard kiosk. Because of widespread dissatisfaction with the GPO's design, the Metropolitan Boroughs Joint Standing Committee organised a competition for a superior one in 1923, but the results were disappointing. The Birmingham Civic Society then produced a design of its own—in reinforced concrete—but it was informed by the Director of Telephones that the design produced by the Office of the Engineer-in-Chief was preferred; as the Architects' Journal commented, "no one with any knowledge of design could feel anything but indignation with the pattern that seems to satisfy the official mind".Stamp 1989, p. 5. The Birmingham Civic Society did not give up and, with additional pressure from the Royal Institute of British Architects, the Town Planning Institute and the Royal Academy, the Postmaster General was forced to think again; and the result was that the RFAC organised a limited competition.

The organisers invited entries from three respected architects and, along with the designs from the Post Office and from The Birmingham Civic Society, the Fine Arts Commission judged the competition and selected the design submitted by Sir Giles Gilbert Scott.New Telephone Kiosks", The Times, 28 March 1925, p. 9 The invitation had come at the time when Scott had been made a trustee of Sir John Soane's Museum: his design for the competition was in the classical style, but topped with a dome reminiscent of those designed by Soane for his own family mausoleum in St Pancras Old Churchyard, and for the mausoleum for Sir Francis Bourgeois at Dulwich Picture Gallery, both in London. However, Gavin Stamp thinks it "unlikely" that Scott was directly inspired by either of these precedents, arguing instead that "a dome above segmental curves is, in fact, a logical solution to the geometrical problem of designing a sculptural termination to a square pillar when a flat top is not suitable".Stamp 1989, pp. 9–10.

The original wooden prototypes of the entries were later put into public service at under-cover sites around London. That of Scott's design is the only one known to survive and is still where it was originally placed, in the left entrance arch to the Royal Academy at Burlington House. In 2019, it was listed to Grade II* in "recognition of its iconic design status".

The Post Office chose to make Scott's winning design in cast iron (Scott had suggested mild steel) and to paint it red (Scott had suggested silver, with a "greeny-blue" interior) and, with other minor changes of detail, it was brought into service as the Kiosk No.2 or K2. From 1926 K2 was deployed in and around London and the K1 continued to be erected elsewhere.

K3 The K3, introduced in 1929, again by Giles Gilbert Scott, was similar to the K2 but was constructed from reinforced concrete and intended for nationwide use. Cheaper than the K2, it was still significantly more costly than the K1 and so that remained the choice for low-revenue sites. The standard colour scheme for both the K1 and the K3 was a light stone colour, with red glazing bars.Stamp 1989, pp. 11–12. A rare surviving K3 kiosk can be seen beside the Penguin Beach exhibit at ZSL London Zoo, where it has been protected from the weather by the projecting eaves and restored to its original colour scheme. There is another in use at Rhynd in Perthshire.

K4 The K4 (designed by the Post Office Engineering Department in 1927) incorporated a post box and machines for buying postage stamps on the exterior. Only a single batch of 50 K4 kiosks were built. Some contemporary reports said the noise of the stamp-machines in operation disturbed phone-users, and the rolls of stamps in the machines became damp and stuck together in wet weather. This has been widely repeated (including by StampStamp 1989, p. 13.) but JohannessenJohannesesn 1999, p. 7. chose not to, having found no evidence to support the story. Ten survive with four in public use at Frodsham, Warrington, Whitley Bay and near Tunstall, East Riding of Yorkshire. A fine example of a K4 may also be found outside the station building at Bewdley on the Severn Valley Railway. There is a fully restored K4 (including correct telephone and coin operations) at the Bury Transport Museum, Greater Manchester.

K5 The K5 was a metal-faced plywood construction introduced in 1934 and designed to be assembled and dismantled and used at exhibitions. It is not known how many were produced, and there is little evidence they ever reached more than prototype stage. A replica (constructed using the original drawings) can be seen at the Avoncroft Museum (Bromsgrove, Worcestershire), as part of its National Telephone Kiosk Collection.

K6

In 1935 the K6 was designed to commemorate the Silver Jubilee of George V. It was consequently sometimes known as the "Jubilee" kiosk. It went into production in 1936.Stamp 1989, pp. 13–14. The K6 was the first red telephone kiosk to be extensively used outside London, and many thousands were deployed in virtually every town and city, replacing most of the existing kiosks and establishing thousands of new sites. In 1935 there had been 19,000 public telephones in the UK: by 1940, thanks to the K6, there were 35,000.Stamp 1989, p. 14.

The design was again by Scott, and was essentially a smaller and more streamlined version of the K2, intended to be produced at a considerably cheaper cost, and to occupy less pavement space. The principal differences between the two designs were: Size. The K6 was tall and weighed 13.5 cwt (0.69 tonnes). This compared with and 1.25 tons (1.27 tonnes) for the K2. Elements of the design were simplified and streamlined, in keeping with the "moderne" aesthetics of the 1930s. The Grecian fluting was removed from the door and window surrounds, and the previously separate pediment and frieze were merged. The Crown motif (see below), which had previously been pierced through the ironwork to give ventilation, was now embossed in bas-relief. A new, separate ventilation slot was provided. A new glazing pattern was introduced. The door and two glazed sides of the K2 each had 18 equal-sized panes of glass arranged in 6 rows of 3. In the K6 the number of rows was increased to 8, and the central column of panes was made considerably wider than those to either side. This improved visibility, and gave a more horizontal appearance to the windows, again in keeping with "moderne" principles.Stamp 1989, pp. 14–15.

The K6 has since become a British icon, but it was not universally loved at the start. The red colour caused particular local difficulties and there were many requests for less visible colours. The Post Office was forced into allowing a less strident grey with red glazing bars scheme for areas of natural and architectural beauty.Stamp 1989, p. 16. Ironically, some of these areas that have preserved their telephone boxes have now painted them red. The paint colour used most widely today is known as "currant red" and is defined by a British Standard, BS381C-Red539.

Kiosk installation: the early years With continued demand for K6 kiosks, siting them was more widespread than ever before. A purpose built kiosk trailer was designed from 1953 to reduce the running costs of cranes.

Numbers installed The K6 was the most abundant kiosk in the UK and its growth, from 1935, can be seen from the BT archives: + Period Number Notes 1925– 1,000 K1 only 1930– 8,000 K2 & K3 added 1935– 19,000 K6 introduced 1940– 35,000 1950– 44,000 1960– 64,000 1970– 70,000 K8 introduced in 1968 1980– 73,000

Manufacture The K1 and the later K3 concrete kiosks were produced at various (and largely unrecorded) locations, around the country. This made quality control and supervision of the manufacturing process difficult, when compared to the GPO's experience with cast-iron post boxes, and was an important aspect of the GPO's move towards cast-iron telephone kiosks. Over the years, five foundries were involved in this work for the Post Office. Lion Foundry in Kirkintilloch, MacFarlane (Saracen Foundry), and Carron Ironworks near Falkirk all produced batches of the K2, the K6 and the K8. Carron produced the single batch of K4 kiosks. The other two manufacturers were McDowall Steven and Bratt Colbran, both of which produced only relatively small batches of the pre-war Mk1 K6.

Many kiosks have been fitted with replacement backs; unmodified examples usually have the identity of their manufacturer marked on a plate on the outside at the bottom of their back panel. The only exceptions are the few Mk1 models made by Bratt Colbran, which are anonymous. A supplementary way of identifying the manufacturer is by means of casting marks on the various component parts – i.e. LF, CC, MF, MS and BC – which were used to various extents over the years. A more consistent manufacturer mark can be found at about shoulder height on the inner face of the back panel. These marks generally identify both the manufacturer and the precise model of kiosk. Up to around 1949, the year of manufacture is also included. The non-BT K6 kiosks erected later, usually painted black, are for the most part new castings from new manufacturers.

Crown