Plans for the biggest reforms to secondary qualifications in more than half a century have taken a major step forward after a body representing every British university offered support.

Universities UK, which speaks for 90 vice-chancellors, said the Tomlinson review of 14 to 19 education offered “a number of advantages over the current system” for students, higher education and employers.

It said the proposals for a new four-level diploma to replace GCSEs, A-levels and vocational qualifications would encourage and stretch all students.

The universities believe the diploma, to be introduced within 10 years, would help more youngsters from poorer backgrounds into higher education, by giving them clear progression routes.

The vice-chancellors are a crucial constituency for Mike Tomlinson, the former chief inspector leading a government working party putting together the proposals.

He must satisfy them if the plans, at present out for consultation, are to succeed.

In their official submission to the second phase of the 18-month review, Universities UK said they would welcome the chance to get involved in designing courses to be used for the new qualification.

At the moment, the diploma would have a compulsory “core” of maths, communication and information technology, with other subjects optional.

Students would complete a research project and could gain credit for work including community service, sports, art and music.

Universities UK said its framework “should enable and develop both depth and breadth within the curriculum and create a learning environment which will be more flexible and adaptive”.

The Tomlinson group is not due to produce final recommendations for ministers until the autumn, and the Universities UK submission has one major caveat. It says more details of the proposals, including how the new qualification is graded and assessed, is needed and that these will be crucial to its success.

The support of university admissions tutors, who would eventually have to select students on the basis of the diploma, will be just as crucial to its success as the vice-chancellors’ endorsement.

However, the backing will be welcomed by Mr Tomlinson. It follows support from Cambridge university, in a separate response.

Reacting to Professor Steven Schwartz’s review of higher education admissions, Cambridge said that the diploma could give admissions tutors better information than A-levels on which to select students.

It also stood to “prepare all learners better for study within higher education”.

The Tomlinson proposals, which are backed by state headteachers, have been greeted sceptically by some employers and private school representatives.

Insiders say, however, that these groups can still be won over. The final report, which will produce costed proposals for reform, will be crucial.