Zanussi Oven Tripping Electrics?

Hi

We have a built in Zanussi oven. Usually when the oven or grill reaches the desired temperature set on the termostat knob, you hear a"click" and the pilot control light goes out to tell you the desired temperature has been reached. Our oven is still functioning, heating up but as soon as it reaches it's set temperature, the pilot light clicks off and the electrics trip. We've also noticed a slight spark from the thermostat knob.