An ivory coloured, urea formaldehyde, compression moulded, GPO 312L telephone, dated 1954. The 300 series was first introduced by the General Post Office in 1937, providing a telephone with an integral bell (see AIBDC : 008465) in a one-piece moulded case. Developed as the 332 with Ericsson Telephones Ltd (UK), it was based on an earlier model released by Ericsson in 1932, designed by technician Johan Christian Bjerknes and artist Jean Heiberg. Available in black (phenol formaldehyde), Chinese lacquer red, ivory and jade green (all urea formaldehyde), there were seven main versions of the phone produced, the 312 being made available from 1949. It was fitted with a one key plunger and a pull-out drawer with an envelope in cellulose nitrate, providing convenient storage for a list of dialling codes. The No.164 handset is attached via a white 3 core plaited cloth cord. Stamped 312L S54/3A on the base, denotes that this model was made by Siemens Brothers, the L suffix referring to the chrome dial having both letters and figures. The width of the case was specifically calculated to ease gripping when lifting, making this model of telephone more easily portable.