as an electrician, DO NOT do that. If the wrong type of fuse is fitted at the fuse board end you could have a fire. The fan will be wired in 1mm twin and earth, a socket should be wired in at least 2.5mm.
Also, when spurring of sockets you need to make sure that you are spurring of a ring main, eg, both cables in the socket are live, otherwise if its not a radial then it could be a spur already, which could cause a fire.
Dan
ROBERTS & SON ELECTRICAL, June 2009