If it has one, also check the hole where the safety switch striker goes in to make sure it is not full of fluff which can effect the operation of the door switch. We had a small Hotpoint Tumble dryer ( for well over 12 years !) , that had this problem. 2 minutes with a pair of tweezers soon sorted it every few months.
Tim, St Andrews
January 2005
sounds like the safety switch on the door is either open or the peg on the door catch which presses the switch in has broken off.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix tumble dryers.