These plugs and other devices were typically used to plug the iron into the ceiling light. Or a radio, heater, fan and countless other things.
This was necessary as at the time, many properties did not have socket outlets in all or even any rooms, yet most would have a pendant light in the centre of the ceiling.
BEEKA branded double bayonet adaptor
BEEKA branded double bayonet adaptor as used for connecting electric irons into the ceiling light.
BG and an unbranded Empire Made dual adaptor
Two dual bayonet switched adaptors to provide a power socket from a ceiling light pendant.
BS52 bayonet plug to a 2 pin socket
Examples of adaptors with a BS52 bayonet plug at one end and a BS372 two round pin socket at the other..
Bakelite adaptor to flash lights on and off
Small bakelite adaptor which fits into a bayonet light fitting to flash the lamp on and off for festive, decorative or other purposes.
Double Socket Bayonet Adaptor
An unusual adaptor to connect two small bayonet plugs together with no provision for any wiring - meaning one plug would supply power to another plug..
Volex V410 Heat and Light switched bayonet adaptor
Brown bakelite Heat and Light double bayonet adaptor by Volex with pull cord switch. Includes original box..
Connecting appliances to the lighting circuit in this way has several problems. The bayonet plug has no provision for any earth connection, and items such as electric irons usually required one.
Lighting circuits in the UK were typically fused at 5 amps, and not designed for the connection of higher rated items such as irons or heaters. While the fuse should blow, the rewireable types typically in use could easily be bypassed with other sizes of fuse wire, hair pins or various other random pieces of metal.