Tumble dryer only works for about 5 mins?

I set the timer to 1 hour, or whatever, switch on and it runs normally (heat, drum turning, everything ok) for about 5 minutes. Then suddenly it is at zero and it has stopped, so I can only have about 5 mins drying at a time. Any ideas what has gone wrong here? Seems like a faulty timer to me and I'm wondering if it can be fixed or if that is it.
We have de-fluffed it and made sure that the pipes are all clear and flowing freely.
It is an Indesit IS60V 6kg model.