<P> The paint colour used most widely today is known as "currant red" and is defined by a British Standard, BS381C - Red539 . This slightly brighter red was introduced with the K8 model in 1968, but went on to be used across the estate on previous models too . Hence, for complete historical accuracy, any kiosks in pre-1968 settings should really be painted in the previous, and slightly darker, shade BS381C - Red538 . </P> <P> The first standard public telephone kiosk introduced by the United Kingdom Post Office was produced in concrete in 1920 and was designated K1 (Kiosk No. 1). This design was not of the same family as the familiar red telephone boxes . As of 2017, there are six K1 boxes in existence, all of which have been listed at Grade II by Historic England, with two still located on British streets . The first is situated in Trinity Market in Kingston - upon - Hull, and the other, in Bembridge High Street, Isle of White . </P> <P> 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 . </P> <P> 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 .' 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 . </P>

When was the first red telephone box invented