Plug Adaptors
Plug adaptors permit two or more plugs to share one socket, or allow the use of a plug of different type. There are several common types, including double- and triple-socket blocks, shaver adapters, and multi-socket strips. Adaptors which allow the use of non-BS 1363 plugs, or more than two BS 1363 plugs, must be fused. (Note, "adaptor" is the normal British spelling (as opposed to "adapter") and is used throughout BS 1363.)
Read more about this topic: BS 1363