Nick Clegg today admitted he "should have been more careful" when he signed a pre-election pledge to oppose a rise in tuition fees.
But the Deputy Prime Minister said he would not ignore the problem by putting his "head in the sand", and said the Government's policy would help generations of poor people go to university.
He told Daybreak: "In politics, just as in life, sometimes the things that you want to do, it turns out that you just can't do them. And then you just simply have to do the right thing with the kind of tools that you have available.
"I guess the easiest thing for me would have been for me to say I've signed this pledge, I'm going to put my head in the sand, I'm not going to come up with a fair sustainable solution to universities and simply refuse to deal with it.
"I don't think that would have been the right thing. I wouldn't have been able to live, now that I'm in government, with the idea that because, yes, I had a policy before we went into government that I now realise we simply can't implement in practice, that I wasn't going to try and put something in place that will really help generations of particularly poor, bright kids who don't presently go to university.
"That's what I'm trying to do, but I'm very open about the fact that, yes, I had a policy, we had a policy before, that we now can't deliver."
In the Commons yesterday Mr Clegg came under attack for his u-turn as he stood in for David Cameron at Prime Minister's questions.
Labour's deputy leader Harriet Harman said Mr Clegg had been "led astray" by the Conservatives during the negotiations to form the coalition Government.
The Lib Dem leader today admitted his party should not have included the anti-fees policy in their election manifesto.
"I should have been more careful perhaps in signing that pledge.
"At the time I really thought we could do it. I just didn't know, of course, before we came into government, quite what the state of the finances were.
"We didn't win the election outright. This is also part of a compromise in a coalition government," he said.