Professor Stephen Hawking has called on Gordon Brown to release cash withheld from a Gloucestershire college.
Last month Cheltenham's National Star College was told a grant of more than £5m from the Learning and Skills Council (LSC) was being withdrawn.
The money was to improve capacity and facilities for students with complex physical disabilities.
Professor Hawking has asked the prime minister to find funding to "enable this invaluable project to go forward".
He has written a letter to Mr Brown with his daughter Lucy, who is vice-president of the college's fundraising appeal.
They said: "On the basis of the unique and national nature of the college's provision and the extremely specialised needs of its students we write to urge you to reconsider the funding position of the National Star College."
The world-famous physicist originally met students from the college at the Cheltenham Literature Festival in 2007.
The college was one of more than 140 that had their building projects frozen by the LSC in December after money for a multibillion-pound government re-building scheme ran out.
The college, which caters for 350 students, expected to receive funding to help complete the major part of its building work, including creating new classrooms, and accommodation for students.
Earlier this month, college representatives met with Further Education Minister Kevin Brennan, and a petition on the Downing St website has gained 3,149 signatures so far.
Kate Green, the college's capital appeal director said they have redeveloped part of the campus, but it opens out on to "wasteland".
"It's a great period of uncertainty for everybody at the college, student and staff," she said.
"This is something that's so important for the future of the college.
"We are all struggling to come to terms with it, we are all hoping they will change their minds."