Found the link for you...
The ICSTIS governs the use of Premium Rate numbers in the Uk.
Information about what you can and can't do can be found there to start with...
ICSTIS - Regulations
This may also be of interest if you can't get your own set up with BT:-
Talior Made Premium Package
They give you a number and provide the operators according to the site.... You promote the number and split the revenue.
Good luck mate anyways.... BT's site is a bitch to find anything on now.