One 5A plug with three 5A sockets.
These are BS372 pin spacing, although neither is marked with any standard.
UK REG.DES NO. 622168
Made in England
MAX LOAD 5A. 250V.
In reality, this would be useless, as the whole assembly is still limited to 5A.
The patent is dated 13 February 1930, applicant A.P. Lundberg and Sons Ltd. It refers to electrical adaptors of the type shown here.
The adaptor is held together by the pins, both of which are threaded and screw into the bekelite body.
There is no fuse - connections are staight from the pins to the sockets.