From the press release from 'Channel Five':

"This young lady went from alive to dead in just a few days, thanks to our crack team of 'corpse trainers'; actors who have appeared in countless episodes of 'The Bill' and 'Casualty' on anything from a morgue slab to a hospital trolley. She worked for week to eventually make it through to a final where she had to lie down alongside four real corpses, then a group of celebrity mortuary attendants had to guess which one was the faker. We don't want to spoil the surprise about who won, but let's just say that all those hours training a hand-picked group of flies to swarm out of her mouth on cue wasn't wasted". Presented by Richard Blackwood.