Three Oxford University academics are making a bid for eternity by signing up with the Cryonics Institute in Michigan to have their bodies frozen upon death in the hope of being brought back to life later.

The procedure would cost Nick Bostrom, a professor of Philosophy, and researchers Anders Sandberg and Stuart Armstrong at least £50,000 each. Mr Armstrong wants his whole body frozen, while Messrs Sandberg and Bostrom would have only their heads frozen, using a mixture of antifreeze chemicals and kept in liquid nitrogen at minus 196 degrees Celsius.

Mr Armstrong's wife, Miriam, is pregnant and the couple wants to include the yet-to-be born baby in the experiment with the hope that they will one day come back to life when there is available technology.

The four are among the almost 1,000 people who have trusted that the Alcor Life Extension Foundation, based in Arizona, will bring them back to life one day. Reports said that celebrities who are also open to the idea include singer Britney Spears, socialite Paris Hilton and former American Idol judge Simon Cowell.

So far, Alcor has 117 human bodies in its freezer and some frozen pets.

For those who opt for the body freeze, their corpse is attached to a machine which maintains blood circulation. For those who prefer the head only option, like Mr Sandberg, they are hoping for the availability of technology that would enable their personality and memories to be downloaded to a computer and later transferred to another living human body.

In opting for the head-only choice, Mr Bostrom, quoted by Daily Mail, said, "The more uncertain you are about the future, the more it makes sense to keep your options alive - for example, by trying to preserve as much as possible of the information content in your brain, rather than throwing it away."

The other technology that he would need is one that could clone a human body on which the unfrozen head would be attached eventually.

Part of the growing popularity of cryonics is it being featured in TV shows and movies such as this one posted on YouTube.