Mr Darling said: "These extra places allow us to strengthen our offer for young people and ease parents' concerns that their first child's taste of life after school and college will be a prolonged spell on the dole queue.
"We have seen in past recessions what a potential waste this was and the long-term damage that it caused".
At a cost of £250m over three years, there will be 10,000 more full-time honours degree places, 5,000 part-time honours degree places and 5,000 foundation degree places.
A further £20m will be available for the funding council to find ways to improve efficiency.
The funding for the new places offsets the 6,000 fewer university places that were to be available next year, according to the funding councils. This means that in real terms there will be 14,000 more places than last year.
The chancellor said that, with almost 400,000 more young people going onto university than in 1997, the investment in the sector was "unprecedented".
But he warned that alongside this one-off funding, universities would have to make "efficiency savings" and focus their attention on "quality teaching and research".
The chancellor also promised £35m for a university enterprise capital fund for university innovation and ideas to help strengthen links between universities and businesses.
"We need to invest in skills and education and young people," said Mr Darling.
Business Secretary Lord Mandelson said: "This further investment will allow universities and colleges to build on their success and continue to expand, offering 20,000 funded places this autumn through a range of degrees students want in the subjects which business and employers most need."
The promise of extra places at a time of record demand was welcomed as a "lifeline" by the National Union of Students.
NUS president Wes Streeting it would "help to ensure that many students with the ability and aspiration to benefit from higher education will not be left out in the cold this autumn".
The University and College Union welcomed the news of extra places but asked who would teach the extra students.
Universities are facing a 23% increase in applications
The lecturers' union general secretary, Sally Hunt, said: "Extra places for students should be a cause for celebration, but with jobs at risk in both universities and colleges we will inevitably see larger class sizes and increased workloads for staff who survive the cull.
"Anyone who doesn't think this will lead to a drop in the quality of education is sadly misguided."
Universities UK, the representative body for universities, welcomed the extra places.
Professor Steve Smith said this was a "tremendous outcome for the sector and a sound investment in the UK's knowledge economy at this crucial time".
Institutions will now be invited to bid for a share of the modernisation fund.
Applications to UK universities have soared by more than a fifth, increasing pressure on places for courses starting in the autumn.
Figures from the university admissions service, Ucas, published last month, showed a 22.9% increase in applications on last year.
Mr Darling also announced extra measures to tackle youth unemployment by extending until March 2012 a guarantee of a job or training for every 18 to 24 year-old after six months out of work.
The chancellor said he would not make immediate cuts in public spending because this would risk "derailing the recovery".
But he warned the next settlement from 2011 was likely to be the "toughest for decades".
Liberal Democrat universities spokesman Stephen Williams, said: "These extra places will make little difference when it comes to easing the pressure on places this year.
"Labour encouraged young people to apply to university and now it has dropped its 50% participation target and record numbers of bright young people are set to be turned away."
Mr Darling also confirmed plans for £1.1bn savings from the Department for Children, Schools and Families.
This will mean £950m in savings from schools and £150m from 16-to-19 provision and Sure Start children's centres.
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