The hour is very late, and the job is very lonely. Michael Martin is just 14 hours away from telling Parliament that he is quitting the job he loves, and to which he had clung so hard.
The man in the dark blue shirt with the buttons undone at the neck and the sleeves rolled up has already made up his mind to go. That decision came eight hours earlier, shortly after his disastrous Commons appearance, when he dead batted questions from MPs who were demanding that he go.
Having muddled through that ordeal, seemingly oblivious to how untenable his position had become, he walked back along the private corridor, down a back staircase and across a small courtyard, to the magnificent grace and favour house overlooking the Thames that has been his home for nine years.
As Martin settled down to reflect on the ghastly ordeal he had just been put through, an unexpected visitor dropped by. It was Gordon Brown, who had pointedly just walked out of the chamber while Martin faced the wrath of backbench MPs.
Brown's demeanour was more in sorrow than in anger. He and Martin have known each other in the narrow world of Scottish Labour politics for more than 25 years and get on well. There is no mutual animus.
But despite the closeness Brown had to steer his way carefully through this conversation, because a prime minister has no authority to sack a speaker. On the contrary, it is a pillar of Britain's unwritten constitution that in Parliament, the prime minister defers to the authority of the speaker, not the other way round. That is why Brown went to Martin's house, rather than summoning him to Downing Street to say what he had to say.
Though he did not say to Martin "you're fired", Brown did have a powerful bargaining chip. Michael Martin had just announced to the Commons that he was calling a meeting within 48 hours of the leaders of all the political parties to discuss reforms that would prevent the MPs' expenses scandal from being repeated. Martin was desperately anxious that the meeting should happen, and be a success. Brown broke the news to him that it was not going to happen if he was seen to be clinging obstinately to his job.
Brown did not even need to threaten to boycott the meeting. He needed only to point out how difficult it would be to persuade the Liberal Democrat leader, Nick Clegg, to co-operate, given that he was on the verge of adding his name to the motion of no confidence in Martin.
David Cameron had also visibly lost patience with the Speaker. And the Government might not be able to resist pressure to allow that unprecedented debate on whether to sack the Speaker that backbench MPs were demanding. Martin listened quietly and promised to think carefully about what Brown had said.
Friends hinted yesterday that Martin had actually already made up his mind that he would have to make an announcement about his own future soon. He would have liked to preside over the meeting of party leaders. To be seen by the public to be energetically clearing up the mess for which he was being held responsible, so that when the reform process under way, he could announce that he was stepping down at the next election and leave with his reputation at least partly restored.
But after Brown's visit, it became painfully clear to the lonely Speaker that he could not take charge of the reform process while his authority was in shreds, and if he tried to cling to office, he might be humiliatingly prised out, with the Prime Minister declining to lift a finger to save him. As the photo shows he was still talking late into the night.
But after a long evening, he slept on the matter, and rang Downing Street at around 9.30 yesterday morning. He did not even stand on his dignity and demand to speak personally to Gordon Brown. A cabinet meeting was drawing to a close when Brown's private secretary passed him a note telling him of Martin's decision. Brown read it and put it away, without saying a word.
Soon afterwards, the Prime Minister was seen in the courtyard outside the Speaker's house, setting off a rumour that he had been to see Martin again.
Actually, he had been driven there so that his car could be parked in the Speaker's courtyard while he took part in a meeting of Labour's National Executive to discuss disciplining Labour MPs implicated in the expenses scandal. Downing Street said emphatically that he did not meet or speak to Martin yesterday until all the party leaders convened in the Speaker's house for their meeting at 4.30pm.
Meanwhile, just before 2.30pm, Michael Martin put on his ceremonial robes and took his place in the procession that marks the start of each day's proceedings in the Commons. By now, the news that he was resigning had been on the airwaves for four hours, after being leaked to Scottish TV, and a surprise was awaiting Martin that must have softened the pain of his traumatic day.
The daily procession always passes through Parliament's central lobby, where members of the public are allowed to stand and watch. Normally, they line the Speaker's route is solemn silence, but yesterday there was a spontaneous outburst of loud applause as the doomed Speaker paraded by.
It is unlikely that the public were clapping the pig's ear that Michael Martin has made of the MPs' expense controversy. It is more likely that they were paying tribute to the remarkable life of a man who rose from a council estate in one the roughest areas of Glasgow to the highest ceremonial office in Parliament.
Martin again addressed a packed House to lay out the timetable for his departure. His statement lasted less than a minute.
"Since I came to this House 30 years ago, I have always felt that the House is at its best when it is united," he said.
"In order that unity can be maintained, I have decided that I will relinquish the office of Speaker on Sunday June 21. This will allow the House to proceed to elect a new speaker on Monday June 22. That is all I have to say on this matter. Order."
Although the parliamentary sketchwriters have unkindly nicknamed him "Gorbals Mick", Martin did not come from the Gorbals, but from Anderston, and was never known to his friends as Mick. He is, though, a Roman Catholic, the first to hold the office of speaker since the Reformation. He was born on 3 July 1945, the son of a heavy drinking merchant seaman, and worked in a railway yard as a sheet metal worker, then became a shop steward with the engineering union, the AUEW, at a Rolls-Royce plant. His union connection helped him secure the safe seat of Glasgow Springburn in 1979.
Realising that he was never likely to be a star performer in the House of Commons chamber, Martin concentrated on working within committees, particularly the committees that ran the Commons and looked after MPs' welfare, building a network of friends and contacts. When Betty Boothroyd stood down in 2000, it was assumed that a Labour speaker would be followed by a Conservative, as Tony Blair and other ministers voted for the eventual runner-up, Sir George Young. But Martin won, with overwhelming support from backbench Labour MPs.
He repaid them by looking after their interests assiduously. When Heather Brooks, a freelance journalist, submitted a Freedom of Information request for details of MPs' expenses, Martin presided over a long legal battle to protect them from the public gaze. But when police wanted to raid the Commons office of the Conservative shadow minister Damian Green last year, they were obligingly given permission, exacerbating Conservative suspicions that, instead of looking after the welfare of Parliament, Martin was behaving like a shop steward for his friends on the Labour side.
He did his standing no good when he ungenerously disclaimed responsibility for the police raid, blaming the newly promoted Serjeant-at-Arms, Jill Pay.
Martin had already acquired a reputation for treating his staff badly, driving several to resign. For instance, his press spokesman, Mike Granatt, had been briefing journalists that the £4,280 which the Speaker's wife, Mary Martin, had claimed for taxis had been "entirely in connection with household expenditure that supports the Speaker's duties". When Granatt discovered that this was not so, he announced that he could not work with the Martins any more.
As recently as two years ago, Martin's position seemed so secure that Labour activists in Scotland were talking about him as the founder of a political dynasty. His son, Paul, was elected to represent Glasgow Springburn in the Scottish Parliament, and seemed to be in pole position to inherit his father's Commons seat, but Paul Martin has since let it be known that he does not want to move to London, seeing his family only at weekends and living under the shadow of his father's patronage.
Michael Martin must have spent a lonely night amid the splendour of his grace and favour apartments. He will never live amid such splendour again, yet one friend said that he seemed to be relieved that it was all over, and was looking forward to spending more time with his grandchildren.
Made in Glasgow: The scourge of traditionalists
Constituency: Glasgow North East
Background: A former sheet metal worker and union official who became a Labour MP in 1979. Elected Speaker in 2000. A teetotaller, he was regarded as to the right of his party on issues such as abortion and homosexuality.
Personal life: He has two children with his wife, Mary. His interests include hill walking, local history and piping. He is also the first Roman Catholic to serve in the role since the Reformation.
Controversies: Angered traditionalists by shunning the tights and silver-buckled shoes worn by past speakers in favour of dark flannel trousers. Last year, he allowed police into the Palace of Westminster to search the office of Conservative MP Damian Green, prompting several MPs to suggest he should stand down and forcing him to make a statement in his defence. Castigating MPs in the House for talking to the media during the expenses scandal proved to be the last straw.
One historic day: What they said
"One burnt offering cannot change the culture at Westminster. The politicians, who seem so set on human sacrifice, have steered clear of the more difficult course – and that is genuine and deep reform of the Commons."
Ken Ritchie: Chief executive, Electoral Reform Society
"It is a bit like a lot of people in a lifeboat slinging one person out in the hope that the water won't now lap over us."
Frank Dobson: Former cabinet minister
"He has been a Speaker who had actually tried to prevent some of this information coming out – part of what seemed to be a very, very small coterie of the Establishment who wanted things not to change."
Kate Hoey: One of the MPs whose public rebuke by Mr Martin focused discontent with his performance
"Michael Martin's resignation today as Speaker is an act of great generosity. The House owes him a great debt of gratitude."
Harriet Harman: Commons Leader
"It had to happen. It was not a nice business. It's been extremely unpleasant work. I did this regretting I had to do it. This gives us a unique opportunity now to create a new House of Commons that is not a caste apart. We have to modernise the building and make it suitable for the age of YouTube."
Douglas Carswell: Tory MP who led efforts to oust the Speaker with a motion of no confidence