Lord Stewart Wood stood at the side of the room; unshaven, grey-faced, exhausted. Around him, Labour Party staff who had worked 20-hour days for much of the last six weeks hugged and grasped each other's hands, seeking to give encouragement.
The gathering in One George Street, just on the edge of St James’ Park, had about it the air of a wake. Before the campaign began, few in Labour gave much for its chances. During it, they became convinced that they could win.
Then, in a blink of an eye, hope dissolved in the few seconds that it took BBC presenter David Dimbleby to read the results of the exit poll: the Conservatives were on course for 316 seats. Labour heads shook in disbelief.
Ed Miliband and his team, including Wood and the Derry-born Brian Duggan, had left the Labour leader's Doncaster constituency at 6am to return to London, following a concession call to David Cameron that was described later by the victor as "dignified and gracious".
Entering the room in One George Square, Miliband, who had grown in stature as the campaign went on, believing that his message was getting through to voters, was cheered and applauded. He stood at the lectern, clearly thinking of might-have-beens.
His farewell to a journey that had started five years ago, beginning with the surprise news that he had beaten his older brother, David, for the leadership on the backs of trade unions, took nine minutes 56 seconds to complete.
He began with thanks – to the party’s activists and supporters, its staff and candidates, to the people he met across Britain in the last six weeks. Soon, however, he got to the point to which everyone knew he must.
“Now it is time for someone else to take forward the leadership of this party. So I am tendering my resignation, taking effect after this afternoon’s commemoration of VE day at the Cenotaph,” he said.
“I want to do so straight away because the party needs to have an open and honest debate about the right way forward, without constraint,” he went on. His words were greeted with silence; a few held back tears.
Labour's National Executive Council will meet early next week to decide the timetable for the leadership battle to come, and also the deputy leadership being vacated by Harriet Harman. Everything should be settled before Labour's annual conference in September.
In 2010, Miliband won because he secured the support of a majority of the trade unions affiliated to Labour; but he did not receive the support of a majority of MPs and party members. The result helped Fleet Street’s right-wing press to portray him as a creature of the unions.
Next time, his successor will benefit from one of the changes to the party’s structures brought in by Miliband, where each member will have one vote, rather than the multiple votes that were enjoyed by many up to now.
In addition, only trade union members who have ticked a box to affiliate personally to Labour will be able to vote. Instead of an electorate of two million, the number entitled to cast a ballot this time will fall to little more than 250,000.
Five years ago, there was a belief among many in Labour that the leadership race that began after Gordon Brown took too long to complete, giving the Conservatives acres of time to convince British voters that Labour had spent too much in office.
Now, however, there is an acceptance that Labour must look into its soul, if it is find a road back into the affections of voters – who, in the end, were convinced by the Conservatives’ message that it could not be trusted with the economy.
"The worst mistake would be in thinking that changing the captain solves everything. If the ship is going in the wrong direction then nothing changes," said the acerbic former Labour Northern Ireland secretary, Lord John Reid.
Labour, he said simply, had “been on the wrong side of all of the main arguments” of the campaign – wealth creation, the economy, public service reform, but also immigration – the issue that dominated in constituencies where Ukip was able to garner nearly four million votes, but not seats.
Under Miliband, Labour went to the left. Believing genuinely that working people have lost out, Miliband pushed against economic “predators”, demanded state control of energy companies and landlords, and a reversal of National Health Service reforms.
On the day that Miliband was elected to take the party's helm, a union leader told Neil Kinnock, who had led the party in the dark days after Michael Foot stood down following the 1983 general election debacle, that the Labour left "had got its party back".
For Reid, the union man’s declaration and much of the Miliband agenda was worthy self-indulgence: “If you want your party back and nobody supports you, you can be indulgent,” he said dismissively.
Remembering the days of Tony Blair and New Labour – a rejected creed during the Miliband years, Reid asked: "Why did Labour win three stunning victories, capturing even the south of England. " The answer is simple: politics is won in the centre-ground, wherever that happens to lie.
Echoing the opinions of others within the party, Reid accepted that Miliband and Labour had run a strong six-week election campaign: “But elections are won, or lost during a campaign. They are won in the years before it begins.”
Five years ago, London Labour MP Kate Hoey began by nominating left-winger John McDonnell for the leadership in 2010, before backing Diane Abbott after he withdrew, before, in the end, voting for Miliband, rather than his brother.
Though she was in the end no fan of Tony Blair, Hoey appeared to appreciate some, if not all, of his legacy: “We have gone from wanting to appeal to the whole country. We’ve gone back into comfort zone, almost tribal again.”
Significantly, perhaps, Labour's rebirth has been eased a little by the decision of voters in Morley and Outwood near Leeds to reject Ed Balls, the one who had dreamed that today he would have been given the keys to the Treasury on Horse Guards Parade.
Balls has been part of Labour’s problem. Labour lost the argument about its economic competence during the Gordon Brown years. With him gone, Labour may have the chance to begin anew, if it makes the right decisions in coming months, but the journey will be hard.