I am in the UK.

If I wanted electrical power from an ordinary ceiling lampholder like
one of these:

http://www.connectstores.com/P.E.D/images/Cl003.jpg
http://cpc.farnell.com/productimages...rd/7947676.jpg

then it used to be possible to get cyclindrical electrical plug which
bayonetted into the lampholder. A couple of wires could be attached to
that plug and that way it was possible to use power from the light
socket.

Are such things still available?

Or have they been outlawed by some safety regulations?