I had a call last week. Kitchen sockets are all off except 1, all circuit breakers and RCDs are switched on. Sure enough all that proved to be true.
Next to the working socket was a FCU for the under cabinet lights that had never worked. Yep, Kev kitchen fitter had wired the cupboard lights into the supply side and left the lights unplugged from the socket provided for them above the units. The rest of the kitchen, 3 above counter double sockets, fridge socket, and washer/drier socket were off the load side.
Washer had been put on, wife was heating up the iron, husband decided to make some toast, one blown fuse. I think the fuse did well to make it 8 years without popping.