either the one shot thermal cut outs have tripped or the heting element is gone or the timer switch is shot.
start in this order. check everything is clear, no fluff build up in the air ways.
remove the back panel and check the two thermal switches with a multi meter, they should both be closed circuit. they cost between and 5 and 10 quid to replace. you can shorrt them out to prove that they are the problem. you can even pull them apart and reset but i don't really recomment that.
John Boy, January 2010