Prime Minister Gordon Brown has announced his intention to stand down as Labour leader, as the party begins formal talks with the Liberal Democrats about the possibility of forming a government.
Here are some of the first reactions to Mr Brown's statement:
LIBERAL DEMOCRAT LEADER NICK CLEGG
Nick Clegg: Brown resignation "could be important"
"Over the last four days we've been working flat out to seek and reach an agreement on the stable government, at last, I think the British people want and deserve. We've had some very constructive talks with the Conservative Party and I'm very grateful to David Cameron and his negotiating team. We've had some very positive talks, made a great deal of progress, but we haven't yet reached a comprehensive partnership agreement.
"That is why, given the urgency of the need to have a resolution to this whole situation, we think it's the right thing, the responsible thing to now open talks - on exactly the same basis as we've been having with the Conservative Party - with the Labour Party, whilst of course continuing our discussions with the Conservatives.
"Gordon Brown has made an important announcement today. It must have been a very difficult thing for him to say personally, but I think he's taken it in the national interest, and I think his announcement could be an important element in the smooth transition towards a stable government that people deserve, without, of course, prejudice and without predicting what the outcome of the talks will be between ourselves and the Labour Party."
FORMER LABOUR HOME SECRETARY JOHN REID
"I think the decision to try and enter a Lib-Lab pact, coalition, is potentially a disastrously wrong one for the country, for the party and for Gordon himself.
"For the country, because I think it's inherently unstable; it doesn't match up. I think from the point of view of the electorate, the two losing parties trying to usurp the role of the major party - although I disagree with that party - will not be welcomed. I think that from the point of view of cobbling together the necessary numbers, to rely on the Scottish Nationalist and the Northern Irish as we would have to, their demand will be that the English get all the cuts.
"I think the electorate will wreak their revenge on the Labour Party. And that's my interest, in the future of this party."
TORY SHADOW SCHOOLS SECRETARY MICHAEL GOVE
"I can understand why the Labour Party have made this pitch but I think that the Liberal Democrats and the country have a clear choice. If we have a stable, Liberal Democrat-Conservative coalition we can be certain that over the next four years we can govern in the national interest.
"We can also be certain that someone who is actually presented to the British people as a potential prime minister is that prime minister. And we can also be certain that the British people will have a chance to decide whether or not we have voting reform or not.
"If the Liberal Democrats choose - and of course it's their decision - if they choose to join with the Labour Party then we will probably end up with someone as prime minister who didn't go through the process in the general election of scrutiny by the electorate. We'll have the second unelected Labour prime minister in succession.
"It will also be the case that the government will be more fragile at a time when we need strength and stability. And it will also be the case on the basis of the prospectus that Alistair [Darling] and his team have laid out that we will have a change in the voting system without the British people having had a chance to vote on it on a referendum."
LIBERAL DEMOCRAT LORD STEEL
Lord Steel: "He has put the interests of the country first"
"I thought that statement by Gordon Brown was extremely dignified, and I think he's put the interests of the country first by saying that.
"And the fact that he is going to be gone by September is absolutely crucial to any possible negotiations between the Liberal Democrats and the Labour Party.
"It does also put the pressure, of course, on the Conservatives to come up with a better deal than whatever is on offer at the moment - and I hasten to say I'm not involved in that so I'm not talking out of turn, I don't know anything about the current negotiations.
"I think that it does open up a prospect which is more palatable to the Liberals generally if they can get it together."
SCHOOLS SECRETARY ED BALLS
"These days are not the time or place for talking about leadership.
"I am focused on the talks with the Liberal Democrats and delivering our manifesto. The time and the place for leadership is later."
LABOUR'S LORD ADONIS, TRANSPORT SECRETARY
Lord Adonis: "This would be a partnership of principle"
"I hope those discussions are successful and it is possible to form a coalition government between Labour and the Liberal Democrats. Ideologically and in policy terms we are very close together... This would be a partnership of principle.
"I believe it has the capacity to form a strong, stable government, able to take on Britain's economic and political challenges and we will go into those negotiations determined to make them succeed on behalf of the British people.
"No one party can command a majority in the House of Commons. Fifteen million people voted for Labour and the Liberal Democrats combined, last Thursday. Only 10 million people voted for the Conservative Party last Thursday.
"There would be absolute democratic legitimacy behind an arrangement between Labour and the Liberal Democrats. But obviously there are a lot of negotiations to come."
SNP WESTMINSTER LEADER ANGUS ROBERTSON
"After Thursday's result, it was inevitable that Gordon Brown would have to stand down. He has done the right thing.
"From the outset of these negotiations, the SNP have made it clear that we believe a progressive alliance can deliver the best result for the people of Scotland - rather than a Tory government which was resoundingly rejected by the people of Scotland last week, with the Tories in fourth place north of the border.
"We welcome the news that Labour and the Liberal Democrats are now moving towards this.
"The SNP stands ready to work with other parties in an arrangement which will deliver a functioning Parliament at Westminster."
WALES FIRST MINISTER, LABOUR'S CARWYN JONES
"There have clearly been significant problems with the negotiations that have taken place between the Tories and Liberal Democrats in arriving at an agreement.
"Nick Clegg has now instead requested formal negotiations with the Labour Party, with a view to exploring an alternative way forward and this is patently an important development. The Labour Party will engage with utmost sincerity and determination at these negotiations to seek a successful outcome.
"The fact that Gordon Brown is selflessly putting the interests of the country first at this crucial juncture speaks volumes about the man - as both the leader of our country and our party. For this he can only be admired.
"It will be crucial that any new government protects Wales from the brunt of excessive spending cuts."
PLAID CYMRU MP ELFYN LLWYD
"Gordon Brown has done the decent thing following the overwhelming rejection of his premiership last Thursday. It was clear that he had no mandate from the people to maintain his position in Downing Street, and he has now shown that he has heard that message loud and clear.
"Mr Brown's announcement is a signal to other progressive parties that Labour is willing to talk in order to explore the possibility of establishing a progressive alliance to govern in Westminster."
CONSERVATIVE MP NIGEL EVANS
"During the campaign Nick Clegg said that he would more than likely support the party that won the election with the most votes and, funnily enough, that was David Cameron - two million more votes than the Labour Party. And yet we saw Gordon Brown trying to hang on. The fact that he's going in September - I think the country actually passed its verdict: Gordon, they want you to go now. And also they would prefer, I believe, the Liberal Democrats keeping to their word and working with the Conservative Party in the best interests of the country.
"We're in the middle of an economic crisis here in this country. Surely what we need is the Liberal Democrats working in some form of alliance with the party that easily got the largest number of votes, the largest number of seats throughout the country in order to start the work that needs to be done to put this country back on the road."
LABOUR MP DIANE ABBOTT
"I regret Gordon Brown standing down in this way. I think this is a project driven by Lord Mandelson, the better to cut a deal with the Liberal Democrats. However, as a serving MP, I agree with John Reid - the numbers are not there.
"This will not be a sustainable coalition, we will be at the mercy of tiny parties that simply want to protect their nations from the cuts. This can't work.
"Above all what we need as a country is a period of stability. This rainbow alliance with Alex Salmond and 'Uncle Tom Cobley and all' cannot hold together."
LABOUR MP JOHN MANN
John Mann was the first Labour backbencher to call for Mr Brown's departure following the election result.
"It's a brave decision by Gordon Brown, it's the right decision to go now following the election result and it opens all sorts of possibilities.
"The electorate has given a hung Parliament as [its] verdict. It's really uncharted territory the way it's happening and therefore we've got to work this through. But by what Gordon Brown's rightly done today, there are more options available and it allows the Labour Party to look forward into the future as well."
ALISTAIR CAMPBELL, FORMER LABOUR DIRECTOR OF COMMUNICATIONS
"Gordon was always pretty clear that he didn't win that election, and I think the way he's conducted himself since then has genuinely been about trying to steer the country through this very odd constitutional situation."
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.