My SMEG dishwasher has started tripping out the electricity ?

My SMEG dishwasher has started to trip out the circuit breaker when I switch it on. This has happened a couple of times recently, but I put it down to a sensitive cb and also having other appliances on - washer or kettle. But today it is making a noise and there is no water comingin or any or draining sound at the beginning of the cycle (any cycle) and then it trips out the fuse. It is about 5 years old.

Fiona Yates
December 2011