A telephone box dating back to the 1960s has been recognised as 'nationally rare' artefact by Historic England. 

The K8 telephone box, on the southbound platform of Chalfont and Latimer London Underground station in Little Chalfont, is one of four on the London Underground network and is believed to be one of only 50 still in existence.

The kiosk has been awarded Grade II status by the Department for Culture, Media and Sport following a collaborative effort from Buckinghamshire Council's Local Heritage List Team and Transport for London.

Architect Bruce Martin designed the K8 model in the 1960s after winning a competition held by the Post Office.

11,000 K8s were subsequently installed across England, with those on the London Underground intended for staff use only, before the majority were removed by British Telecom in the 1980s. 

The Grade II listed box in Little Chalfont is a dark maroon to match the colours of the Metropolitan Line rather than the bright red of traditional public telephone boxes, a difference designed by Martin to distinguish K8s from their well-known counterparts.

According to Historic England, the telephone kiosk qualified for Grade II protection due to Martin's "meticulously simplified and updated" design, as a "nationally rare survival" of a once common structure and because it contributes to an understanding of the historic development of the communications industry in England. 

Peter Strachan, Buckinghamshire Council's cabinet member for planning and environment, said: "We are delighted that our Local Heritage List team has in some way helped secure national Grade II listing for this iconic piece of cultural and design significance here in Buckinghamshire.

"It's so important that we treasure and protect artefacts like this for future generations to appreciate and enjoy."