It sounds like the the heating element has gone. They can be replaced. The Type and wattage will be marked on it on the part of the element that bolts to the back of the inside of the oven.
It should look something like this
You should be able to get them from somewhere like grange electrical.
The one in my uncles cooker blew recently. I didn't need to test it as it was all warped and the thing had began to melt. you could see it was knackered.