Deputy prime minister Nick Clegg has issued a televised apology to students and voters for breaking a solemn Lib Dem vow not to raise tuittion fees.
A humble-looking Liberal Democrat leader looked directly into the camera and said: "Sorry."
Riots broke out in November 2010 following the government decision to raise university tuition fees to £9,000 a year.
Before the general election in May that year, Clegg and many in his party were pictured signing a pledge to not raise the fees if they were elected.
But the increase went ahead with the bulk of parliamentary Lib Dem support and they have been punished in the polls ever since.
The number of students applying for higher education in 2012 fell, partly over fears among young people of being saddled with big debts.
In his televised apology, Clegg said: "I meet people who are disappointed and angry that we couldn't keep all our promises. Above all our promises not to raise tuition fees.
"To those people I say this: we made a promise before the election that we would vote against any rise in fees under any circumstances but that was a mistake.
"It was a pledge made with the best of intentions but we shouldn't have made a promise we weren't absolutely sure we could deliver.
"I shouldn't have committed to a policy that was so expensive when there was no money around.
"There's no easy way to say this: We made a pledge, we didn't stick to it, and for that I'm sorry."
He said he would learn from his mistake because he owed it to the voters.
The issue has cast a long shadow over his party's achievements in office and poll ratings for the Lib Dems have made ugly reading since the coalition bedded down.
Following the upheaval of the 2010 general election, in which no party won a majority, the Lib Dems have been stuck on between eight and 13 points in opinion polls.
That has triggered speculation over what political future Clegg has.
A move to Brussels has been mooted by Europhile Clegg, who began his political career with the EU there.
This video has been seen by some analysts as a bid to redeem his party in the eyes of disillusioned supporters.
Being in coalition with Conservatives has been difficult for many of the party's grass-roots. Many of them would find Labour a more natural bedfellow for sharing power.