The world's fattest cat has heartbreakingly died at a feline cat camp where medics were trying to help him lose weight.

Vets believe his layers of flab were so deep that scans had failed to show cancerous tumours riddling his internal organs.

The puss, nicknamed Crumbs for his habit of eating every last scrap of food, had been raised on a diet of biscuits and soup in the basement of a Russian hospital before he was found.
Video: NewsX