The method of transplanting animal organs – xenotransplantation – is hugely controversial, as has been tried before with limited success. Many of the organs were rejected by the patients' immune system.

He said: "Pigs' organs are the right size for human transplantation, and they work similarly to human organs. Of course this raises a moral problem, but it is much more ethical to use a pig to save a human life than to use it for relatively unnecessary meat eating."

The government is considering imposing presumed consent, whereby organs would be taken from the dead unless they had specifically expressed a wish not to give them away, although, according to the Telegraph, experts say this will not solve the problem.

The pigs will be bred with about six human genes to prevent patients rejecting their organs. Winston's team will need to prove that the pig organs can be sufficiently modified to survive long-term in the human body.

He says his method could see hundreds of genetically modified pigs reared simultaneously for their organs. Organs could be taken from pigs as young as one year.

Lord Winston is moving the research project from Britain to America after British regulations and a shortage of funding prevented experiments here. The pigs will be bred in Missouri.