The Liberal Democrats are putting education at the centre of their general election campaign with a pledge to protect real-terms budgets for schools, 16-19 colleges and sixth forms, and early years’ education.

“The Liberal Democrats will prioritise education, just as we have done over the last five years because nothing is more central to what we believe,” deputy prime minister Nick Clegg is expected to say in a speech later today.

“Nothing is more important to creating a fairer society where everyone has the opportunity to reach their potential.”

The party is emphasising the difference between its commitment and the “flat cash” pledge for schools made by its Conservative coalition partners earlier this month - which would be likely to result in significant real-terms cuts to budgets.

“In this parliament we have protected the schools budget in real terms and in the next parliament we want to go further,” a source close to Mr Clegg told TES.

The Tories have not made any financial pledges for the early years and sixth forms. “If you don’t protect 16-19 funding then you are not really protecting school budgets because any school with a large sixth form won’t really feel the benefit and will be squeezed at the other end of the school,” the Liberal Democrat source added.

Funding for the pledge is expected to be explained in the party’s full manifesto.

While Lib Dem sources said they were not setting out “red lines” for any coalition talks after the election on May 7, they insist they would fight “tooth and nail” to deliver them if they were part of the next government.

They also dismissed suggestions that the party had lost credibility on education after breaking its pledge at the last election in 2010 to oppose any increase in university tuition fees.

“Don’t judge us by the one policy we couldn’t deliver,” they said. “Judge us by the policies that we did deliver.”

Related stories:

Cameron: schools will face real-terms funding cuts under Tories 2 February 2015

Schools raid maintenance budgets to pay for free lunches - 19 August 2014

London success threatened by cuts plan, councils warn - 26 June 2014