Early release from jail in the US used to be obtained either by impressing a parole officer with good behaviour or digging a hole, following the example of Clint Eastwood in Escape from Alcatraz.

Now there may be a third option: donating a body part.

A state senate panel in South Carolina has created an organ-and-tissue donation programme for inmates and called in lawyers to discuss a more radical proposal that would reduce the sentence of prisoners that are willing to give up their kidneys to transplant patients.

It has been suggested that a kidney donation could wipe up to six months off a jail sentence. Similar incentives could be given in return for bone marrow or parts of the pancreas, lung, liver or intestine. The US faces a chronic organ shortage, with 95,300 patients waiting for organ transplants and 6,700 dying each year as a result of not receiving them in time.

Demand is high. In one well-publicised case, a "fully functioning kidney" was put up for sale on eBay for $5.7 million (£3 million) before the internet auction company blocked the sale.

Trafficking in human organs is illegal and can be punished with five years in prison and fines of $50,000 or more. State senators are concerned that those laws could make their proposed scheme unworkable.

"I think it's imperative that we go all out and see what we can do," the Bill's chief sponsor, Senator Ralph Anderson, a Democrat, said. The senate corrections and penology subcommittee is expected to go ahead with its volunteer programme in prisons to teach inmates about the need for donors, while taking legal advice.

The main issue involves an argument over whether a reduction of 180 days from a prison sentence constitutes "valuable consideration", because federal law says that it is illegal to give such an incentive to a person in return for an organ donation.

Mary Jo Cagle, chief medical officer of Bon Secours St Francis Health System in Greenville, South Carolina, urged the senators to make the scheme work. Others were not so enthusiastic. Melissa Blevins, executive director of Donate Life South Carolina, said: "We want to keep it an altruistic act."

Organ donations

- A suggested answer to the transplant waiting lists is a "futures market", in which a contract would provide for a substantial amount of money to be paid if organs are transplanted successfully after the seller's death

- Estimates for organs in a free market are £8,295 for a kidney and £19,360 for livers

- In 1995 agents were accused of offering money to leprosy patients in Madras to donate kidneys

- A law passed in Brazil in 1998 made all adults automatic donors at death, unless they carried an ID card stamped with the official logo "I am not a donor"