SCOTTISH ministers are under fire over a £21 million "stealth cut" to university budgets.

Opposition politicians attacked the Scottish Government after The Herald revealed the cash would be withheld from the sector.

The money, which will be taken from a fund set up to make Scottish research globally competitive, comes just weeks after almost a third of university output was ranked amongst the best in the world.

Iain Gray, education spokesman for the Scottish Labour Party, said: "The future of Scotland's prosperity will be based on being a world leading knowledge economy.

"The decision to withhold funding designed to help Scotland's universities is a failure to support the hard work of Scotland's scientists and academics over many years. This cut was delivered by stealth, presumably in the hope no one would notice."

Liam McArthur, Scottish Liberal Democrat education spokesperson, added: "We need to hear why SNP ministers have decided to keep hold of £21m of this funding with no explanation where they are diverting the money to.

"This looks suspiciously like a ministerial slush fund being saved up for the election. Students and researchers at our universities deserve to have this money spent in accordance with Parliament's wishes, not put in the SNP's back pocket."

Universities Scotland, which represents university principals, described the move as "challenging".

Alastair Sim, director of Universities Scotland, said: "As this funding has been held back, rather than cut entirely, we are hopeful that the Scottish Government might be able to return it to universities, within year, so they can use it to generate a significant contribution to Scotland's economy.

"The vast majority of universities have improved their performance compared to the last assessment and some have made significant strides ahead and in that context it is disappointing..... that research funding will be spread more thinly across universities."

However, a Scottish Government spokesman said the decision had been taken to give ministers more flexibility over budget priorities throughout the year.

He said: "The Scottish Government will be providing over a billion pounds in funding in 2015/16, having invested more than £7 billion in higher education since 2007.

"Next year our overall provision of funds for Post 16 education and training will rise, reflecting our commitment to new education and training facilities and the reforms that are part of Developing Scotland's Young Workforce.

"As expenditure can vary in the course of the year, we have asked the funding council not to allocate their budget for next year in its entirety in the first instance, as was made clear last year. This provides flexibility going forward to align resources where needed across our funding for post-16 education."