[emeritus]

I have a copy of the third (1956) edition (reprinted 1960, but possibly revised in 1959, going by the copyright notice) of Odhams "Radio, Television and Electrical Repairs". In the section on domestic wiring, you are told how to install a 3 pin 2A socket from an existing lighting point: however, the caption to the drawing refers to "2 pin 2A socket" and the text says that this chapter had been revised according to the 12th edition of the Wiring Regulations that apparently introduced the prohibition of the use of 2 pin sockets and plugs. I would assume that 2 pin sockets were still permissible when the first edition (1948) was published, and might still have been allowable when the second edition (1952) was published, and that when the drawings were revised, the need to revise the caption was overlooked. Possibly 2 pin sockets continued to be available for maintenance/repair of legacy systems?

Notwithstanding the apparent prohibition mentioned in the Odhams book, Woolworths were still selling BS gauge 2 pin 2A plugs and surface-mounted sockets in brown and white in the late 1960's, but AFAIR they did not bear any BS markings. I used to use them for 12V DC, and have read in other posts that they were used for headphones in theatres and churches..