Seven years ago, almost to the day, a quiet stalwart of the British Cabinet had a major wobble about whether he could carry on. He confided to a journalist that the strain on his family was too much, it was an “increasing wrench” to leave home: “I don’t see politics as a career.”

Flash forward to Monday night, when the man, now our new Chancellor announced, with trembling hands (“I wasn’t conscious of them doing that”), that the Government would guarantee Northern Rock, one of the most dramatic interventions in recent financial history.

Not only has Alistair Darling been catapulted from reluctant minister to the second most powerful job in government, head of the Treasury at a time of global financial insecurity, but he has risen almost without trace. As far as much of the public are concerned, our grave economic crisis was being handled by a bushy pair of eyebrows.

After a string of big personality Chancellors — Lawson, Lamont, Clarke, Brown — Mr Darling is mostly known for his extraordinary black and white combo (there was once a beard of a third colour, but that is a different story). How has he ended up here, in charge of our savings in this, the most rocky of weeks?

First, as we settle down in No 11, we ask about the strain he has been under. He moved into Brown’s old flat, the smaller one in No 10 just a few weeks ago, transforming a family home into a lonely bachelor pad. His wife and two teenage children are a long way away in Edinburgh, and in their place are hordes of officials popping up in his living quarters with the latest news of the financial crisis.

“Our home is Edinburgh. I love Edinburgh. I’ve lived there for 36 years now. This, (London) is where I work. Obviously, as my daughter is at school, her mother as you’d expect is there more than here,” he said.

“This is a working office, and you’re very conscious of that fact. Even if you’re in the flat, it’s a working place. In its every nook and cranny you look around and there’s someone else doing something else . . . The last week, it’s been difficult, it’s been tough. I don’t seem to have left either the Treasury or Downing Street for an awful long time, I’m beginning to forget what my house in Edinburgh looks like.”

But, and this is the key to Mr Darling, he did not look tired or harried. He looked in his element. He is one of only three ministers to have served since the first Blair Cabinet a decade ago, (along with Mr Brown and Jack Straw), but his talent was an unusual one: avoiding headlines. He was the Alka Seltzer of politics, killing headaches at social security after Harriet Harman and Frank Field, calming transport after Stephen Byers, appeasing Scotland after Helen Liddell. This has not been Mr Darling’s worst week: it’s been his best. That dark Monday night was the moment he stepped into the sun.

“I’ve never actually gone out of my way to seek absence from the headlines. But I’ve made it very clear, I think last weekend, that ultimately I’m responsible for the conduct of economic affairs, so that goes with the job.”

So what happened to the man, who, in 2000, agonised about the effect his job was having on his children? Much of his ascent since then can be shown in his ever-growing closeness — geographically, spiritually, and politically — to Mr Brown.

It did not start like that: Mr Darling’s great uncle was a Tory MP, his father a Conservative. After much travel due to his father’s work as an engineer (he went to seven primary schools, after which he said that a change of ministerial brief never flummoxed him) he was sent to a posh Scottish boarding school similar to the one Tony Blair attended, and where, as the same age as Blair, he probably encountered the former prime minister on the rugby pitch. He and Blair have friends in common from their school days.

There were even some stories told in Commons bars that Mr Darling, when at the Loretto boarding school, administered canings on younger boys, including Fergus Ewing, husband of the late MP Margaret Ewing.

“What?” he said, half-astonished, half-amused.

“I did not. No. This is a very serious allegation to make, I’d better be careful of the headlines, ‘he furiously denied allegations last night’,” he joked.

“Complete b*******. There was at that time corporal punishment at that school, but I was never at either end of it.”

After training as a lawyer, 25 years ago he became close friends with Mr Brown. Twenty years ago he became an MP in Brown’s neighbouring constituency, five years ago he said that their relationship intensified, now they are also neighbours as Mr Darling was entrusted with the boss’s old job.

“We talk regularly about a whole host of things, not just Treasury but wider things, but we have done for a long, long time. Certainly in the last five years, I doubt a couple of days have gone by without us speaking to each other, very often we spoke more than that,” he said.

“We know each other, we’re friends, we do discuss things, it would have been extraordinary if we didn’t. It’s always been the case that the Prime Minister and the chancellor need to be as one, when that stops happening, then there’s many, many examples of what happens, and usually one conclusion to it.”

He laughed. What conclusion could that be — Mr Darling, like his predecessor, jockeying to be Prime Minister? More embarrassed laughter. Surely though, it must be particularly hard for Mr Brown not to be constantly interfering in a department he ran so tightly?

“No, I know Gordon so well, I’ve known him for 25 years — there’s never been a difficulty.”

So, back when he was thinking of giving it up, did Mr Brown give his friend any assurances of his future career? Mr Darling was tipped as his chancellor almost as long as Mr Brown yearned to be Prime Minister.

“He never made promises. I was very clear to him, that he had no obligation to do anything.”

What then, decided him to keep at the job?

“My children were born after I became an MP, my son was born in 1988, a year afterwards, and my daughter a few years later. Especially for any MP who represents a non-London constituency, it is a wrench to leave home for four or five days a week,” he said.

“It would have been nice to have a job when I could go home at night. Margaret [his wife who gave up her job as a journalist] took the strain of bringing up young kids. It was almost like I was an absent father, I was only there at the weekend.”

He said that the prospect of doing something different didn’t dismay him, but when pushed on this he said that he had never given any thought to what that might be. He is in the “fortunate position” that there isn’t a day in his cabinet career that he hasn’t wanted to go to work, too busy to brood on alternative lives.

“Especially this summer, when I’ve been here almost continuously.”

So he stayed. Any regrets?

“No, none whatsoever . . . Looking back, we are a very happy family.”

When talking technicalities about tripartite financial regulation, his lawyer’s brain lights up, spitting out rapid fire Edinburgh brogue.

“This is a bullet that needs to be bitten,” he said, with a grand plan to guarantee people’s savings up to £100,000. He wanted to end deals done between banks “in smoke filled rooms”, and suggested that, in time, there would be a significant overhaul of the financial system. If Mr Brown’s favourite word was “prudence”, Mr Darling has come up with a completely new buzzword, which is, er, “caution”. He still errs towards caution on the subject of an early election, and says, despite buoyant polls “we have to go into an election with a degree of humility”.

But for a private man in public life, he can have surprisingly strong views. Friends, such as the crime writer Ian Rankin, talk about his love of Coldplay and Pink Floyd, his ability to transform from minister to human being once at home with his family. Three of his four junior ministers are among the most high-profile young women in Parliament, already dubbed “Darling’s Darlings”.

“That’s extremely patronising. I have four very able colleagues. They are doing a good job.”

What about his views on the McCann trial? His backing of them is unequivocal, despite the controversy.

“It’s a tragedy for them. As a parent you can’t even begin to imagine what it must be like to lose a child. Just not knowing must be an absolute agony. I do feel very sorry for them.”

Returning to his own role in the public eye, he said: “I think people might be concerned if they saw

the Chancellor on the front page of Hello! every week. But I don’t think there’s any risk of that happening to me.” he said. But is it possible Mr Darling aims to shrug off the “boring” jibes? “Frankly, those comments are boring in themselves.”

He is not boring. Just – what’s the word? — cautious.

CV

Name Alistair Darling

Born November 28, 1953, in London. He is the son of an engineer, and the great nephew of Sir William Darling, who was Conservative MP for Edinburgh South (1945–1957)

Education Attended the Loretto School, Musselburgh, East Lothian (Scotland’s oldest boarding school). Studied Law at the University of Aberdeen

Previous Occupation He worked as a solicitor in Edinburgh before being called to the Scottish Bar and admitted to the Faculty of Advocates in 1984. Before becoming an MP, he was a member of Lothian Regional Council, and chairman of the council’s transport committee

Family Married to Margaret Vaughan. Has two children – a daughter and a son

Current position Chancellor of the Exchequer

Mission statement Has said that if he is remembered he would like it to be “as the minister who began to eradicate poverty”

Previous positions in Government

— Social Security Secretary (1998-2001). In what would be a feature of future appointments Mr Darling took over his first Cabinet post in troubled circumstances, after Harriet Harman’s resignation

— Work and Pensions Secretary (2001-02). In this post Mr Darling was responsible for spending a third of the Government’s budget. But while in the job he became a target for angry pensioners outraged that their pensions were raised by only 75p a week.

— Transport Secretary (2002-06). Replaced Stephen Byers, during whose tenure Jo Moore sent an e-mail advising that September 11, 2001, was a good day to “bury” bad news. Mr Darling moved towards accepting road pricing. A petition against the policy has collected more than 1.8 million people on the Downing Street website

— Secretary of State for Scotland (2003-06). Though born in London he says that he “feels Scottish”. He was against devolution in 1979 but had become a supporter by the time he was in government. He has attacked the SNP, arguing that there would be no “quickie divorce” if Scotland sought independence

— Trade and Industry Secretary (2006-07). He was a supporter of free trade, and called on countries to fight protectionism and accept globalisation as “a force for good”

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