The UK's national body representing amateur radio and radio amateurs is the Radio Society of Great Britain
My interest in amateur radio began when I was bitten by the bug at around the age of eleven. Although I became very involved with Cray Valley Radio Society back then, followed by the Gravesend club and making a nuisance of myself around the licensed hams of Gravesend and 
Northfleet. Around the time I left school my active participation in the hobby cooled off somewhat - with other priorities, I guess - and a number of years passed when it was very much on the back burner.
So it was a wonderful rediscovery when I got hold of a scanner a few years ago and the magic was almost instantly there again.
I initially held the call sign M0JRQ but have subsequently been licensed G5VZ, the call originally held by Bill Birchall. www.g5vz.co.uk has a lot more information and m0jrq.com is still up.
Local sites and radio clubs
Pontefract radio club: PDARS
RAIBC - The chairty working for radio amateurs with disabilities