By Ian Dunt Follow @IanDunt
The decision to increase tuition fees was the most "heart wrenching" for Nick Clegg, he has admitted.
In a surprisingly honest and heart-felt keynote speech to the Liberal Democrat conference in Birmingham, the deputy prime minister admitted "just how tough" their time in power has been.
"Government has brought difficult decisions. Of course the most heart wrenching for me - for all of us - was on university funding," he told members.
"Like all of you, I saw the anger. I understand it. I felt it. I have learned from it. And I know how much damage this has done to us as a party."
The tuition fees decision, which led to widespread vitriol towards the Liberal Democrats across the political spectrum was "by far the most painful part of our transition", Mr Clegg said.
The party leader argued that the new system, which see graduates pay the fees only once their income hits a certain level, was the best result which could be secured given Westminster's plan to raise contributions.
"The simple truth is that the Conservatives and Labour were both set on increasing fees, and in those circumstances we did the best thing we could," he told delegates.
"But we failed to properly explain those dilemmas. We failed to explain that there were no other easy options."
In a frank assessment of the party's declining poll ratings, Mr Clegg admitted being in government had not been "a walk in the park".
"I suspect none of us predicted just how tough it would turn out to be," he said.
"We’ve lost support, we’ve lost councillors and we lost a referendum. I know how painful it has been to face anger and frustration on the doorstep.
"Some of you may have even wondered: Will it all be worth it in the end? It will be."
But Mr Clegg argued that the Lib Dems had secured key policies on the NHS and human rights despite the relentless attacks on them by the media.
The Lib Dem leader also offered a resolute and non-negotiable commitment to preserving the Human Rights Act in the face of bitter opposition from Conservative backbenchers.
"Let me say something really clear about the Human Rights Act," Mr Clegg said.
"In fact I’ll do it in words of one syllable: It is here to stay."
Labour's shadow education secretary dismissed the apology, saying Mr CLegg was "rewriting history".
"People will not be fooled by Nick Clegg's desperate self-justification. His actions speak for themselves," he said.
"He sought votes pledging to fight savage Tory cuts only to join a Tory-led government days later and back cuts that go too far and too fast. That tells you all you need to know about Nick Clegg."
The speech, which was delivered from memory and in the round, caps off a subdued party conference for the minority party.