In the current RSPCA policy document “Policies on animal welfare” (revised 2003) it is stated that:

“Exotic animals such as snakes, lizards and terrapins often carry disease, are difficult to look after and are rarely provided with adequate facilities. Such animals are unsuitable as companion animals”.

The Federation of British Herpetologists have started a petition to (hopefully) encourage the RSPCA to revice it policy towards herptiles.

Link & more info:
http://www.petitionthem.com/default.asp?sect=detail&pet=994

-obeligz