Nick Clegg has said he was "stuffed" over his broken campaign promise not to raise university tuition fees.
He told North Tyneside factory workers he had no choice but to back the hike in fees after his party "came third" in the General Election.
The Deputy Prime Minister was hauled over the coals by staff at the Bridon International rope factory on the banks of the River Tyne, who said the Liberal Democrats had lost credibility as a political party.
Mr Clegg was unapologetic when he addressed the crowd of around 150 workers following a tour of the factory.
He said he passionately believed the decision to form a coalition Government with the Conservative Party had been for the good of the nation.
Asked repeatedly why he backed the decision to raise fees, he said: "Well, we did not win the election.
"Hang on a minute. People say to me 'Why don't you do exactly what's in the election manifesto?' I'll tell you why - we came third."
Responding to a claim that he should have used his influence to block the policy, he said: "Of course I have influence but I had a real dilemma.
"I was stuffed on this, basically.
"Both Labour and the Conservatives wanted the fees to go up so, if I had gone into coalition with Gordon Brown, fees still would have gone up.
"If I had wanted to go into coalition with the Conservatives, they would have gone up.
"They agreed with each other more than they agreed with us.
"So what we did instead was worked incredibly hard to make sure the system, when it is introduced as it will be next year, is much fairer than it would have been otherwise."
One worker told Mr Clegg the Liberal Democrats should have bided their time to build for the future instead of joining the coalition.
Holding one hand parallel to the floor, he said: "Basically you have gone from there to there and have lost a lot of credibility since joining the Tories."