Professor Stephen Hawking has attacked the Conservatives over their handling of the NHS and accused Health Secretary Jeremy Hunt of "abusing" science to justify policies.
The world renowned scientist, a lifelong Labour supporter, said Tory policies such as the public sector pay cap, imposing a new contract on junior doctors, and removing the student nurse bursary has put the NHS in crisis.
He said the health service was being pulled in different directions by multinational corporations driven by profiting from NHS privatisation and the public, which favours a publicly funded health service.
The 75-year-old, who was diagnosed with motor neurone disease in 1962, said he "would not be here today if it were not for the service" and stressed "we cannot lose" the NHS.
Writing in The Guardian, he went on: "The NHS is in a crisis, and one that has been created by political decisions.
"These political decisions include underfunding and cuts, privatising services, the public sector pay cap, the new contract imposed on junior doctors, and removal of the student nurses' bursary.
"Political decisions such as these cause reductions in care quality, longer waiting lists, anxiety for patients and staff, and dangerous staff shortages.
"Failures in the system of privatised social care for disabled and elderly people have placed an additional burden on the NHS."
Prof Hawking, who is director of research at the Centre for Theoretical Cosmology at the University of Cambridge, renewed criticism of Mr Hunt for "cherry-picking" scientific research into the so-called "weekend effect".
The Health Secretary used his drive to create a seven-day NHS as one of the main reasons for reforming junior doctors' contracts - which led to the biggest walkout of doctors in NHS history.
Mr Hunt has cited studies showing higher death rates at weekends when setting out his argument for a seven-day health service.
But Prof Hawking accused him of suppressing contradictory research to suit his argument.
He wrote: "Hunt had cherry-picked research to justify his argument. For a scientist, cherry-picking evidence is unacceptable.
"When public figures abuse scientific argument, citing some studies but suppressing others to justify policies they want to implement for other reasons, it debases scientific culture.
"One consequence of this sort of behaviour is that it leads ordinary people to not trust science at a time when scientific research and progress are more important than ever."