Johnny VaughanJohnny VaughanChiswick, We Have A Problem.

What happens when you sign for a trip to space, but find you've been taken for a ride instead?

That's the premise of Channel 4's new reality show, Space Cadets, hosted by Johnny Vaughan.

The show aims to fool nine contestants into believing that they've been blasted into space.

They've signed up to visit the final frontier as space tourists. But, in reality, their shuttle will be a Hollywood creation, originally made for the film Space Cowboys.

And the Russian Space Tourism Agency, where they are being trained, is actually a disused base somewhere in the UK.

To complete the illusion of space travel, a giant screen positioned just outside the shuttle will offer a view of Earth from space - complete with a hurricane over Mexico and a view of the UK partly covered in clouds (what else?).

But, the laugh could be on Channel 4, if any of the contestants cotton on to the stunt. They're currently holed up in a secret location, with no contact with the outside world.

Three actors have been placed in the group and will be able to report back on whether there are any suspicions.

Helpfully, all the contestants have been chosen for their suggestibility. Many of them believe in UFOs, and several are pranksters. So hopefully they'll see the funny side when the show ends...