Professor John Fabre, a former president of the British Transplantation Society, said that passing opt-out legislation in Spain was not the reason why the country had achieved a high donation rate.

BBC: Deadline for public to have say on organ donation law

Mr Keith Rigg, a transplant surgeon and vice president of the British Transplantation Society, said that the work was "interesting", but had not yet convinced him that it could work in humans.

BBC: Frozen liver transplant success