The Government has agreed to back down on strict laws planned for embryonic stem-cell experiments after a “compelling case” was made by leading scientists in a letter to The Times.

The letter, published last week, expressed alarm that the Human Fertilisation and Embryology Bill would delay potentially life-saving research by requiring all tissue used to create cloned embryonic stem cells to have the explicit consent of its donor.

The Bill, which is passing through Parliament, was set to outlaw access to most of the tissue banks that act as vast libraries of the genes that contribute to serious disorders.

More than 50 biomedical researchers and administrators, including four Nobel prizewinners, have told ministers that such strict measures would deny stem-cell scientists the use of tissue banks for studying diseases such as muscular dystrophy, Parkinson’s and diabetes.

The tissue banks enable scientists to create cloned embryos that can be implanted with the genetic material of patients, assisting research into how the illnesses develop.

The Government’s justification for requiring “express consent” had been that some patients who agreed to donate cells may not have realised that their tissue could later be used for cloning. The letter in The Times said that the requirement jeopardised years of expensive research and the cultivation of unique tissue samples as raw material for cloning.

As tissue was collected before it became possible to clone embryos in this way, the scientists argued that it would have been impossible for anonymous donors to give permission for their DNA to be used in embryonic stem-cell models of diseases. Signatories included the Nobel medicine laureates Sir Martin Evans, Sir Paul Nurse, Sir John Sulston and Sir Tim Hunt, as well as leading stem-cell experts such as Sir Ian Wilmut, Dame Julia Polak and Professor Stephen Minger.

The Government is also considering changing a second measure in the Bill, which will further limit stem-cell research by blocking the use of any tissue from children even if their parents gave consent.

Ministers were reluctant to consider any changes to the Bill, but after a debate in the House of Lords last Tuesday the Department of Health conceded the need to allow exceptions.

In a letter sent this week to peers who took part in the debate in the Lords, the department concedes: “A compelling case has been made that the requirement for express consent could, in certain circumstances, impose a significant burden in this field.”

Evan Harris, the Liberal Democrat MP who organised the letter to The Times, said yesterday: “Plaudits to the scientists for speaking out and the Government for listening.”

The Bill is due to enter the Commons in the spring.

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