Lady Thatcher opened a US thinktank, Sir John Major became chairman of a multinational investment firm, Tony Blair brokered peace talks in the Middle East. So what then of the famously driven Gordon Brown, whose "relentless" ambition Blair detailed so tirelessly in his memoirs? Today the former prime minister is switching on the Christmas lights in Kelty, a pit village in Fife.

This isn't his sole engagement. Also on the agenda are a visit to a children's project that aims to turn Dunfermline into an eco city and a talk to a group of older students about the radical local roots of American magnate and philanthropist Andrew Carnegie. But it's all rather low-key for a man who was the longest serving chancellor since Gladstone and took the initiative when the global financial system was about to collapse in October 2008.

"It may seem strange to other people, but I feel at home," says Brown. "I am happy trying to do things here."

So he's not tempted by a few lucrative directorships and a peerage? Brown is appalled at the idea. "I am not going to the House of Lords. Never. That's not who I am. That's not where I am. I want to do something for Kirkcaldy and Fife. I am a full-time MP, not a businessman."

Outside in the sharp late-autumn sunshine, the rolling landscape rushes by. In the front seat of the Range Rover sits an officer from Special Branch. In the back lies a Muffin The Mule DVD. His past, present and future neatly summed up: the trappings of the premiership, the constituency MP, the father of two young sons.

"Other prime ministers leave office and stay in London," says Brown. "I have come back with my whole family to Fife. This is where they are being brought up. It is better for them and better for me. It's great to see more of the kids."

After losing power in May, Brown returned to Scotland to think, to write, to regroup. Little has been seen of the man who, with Tony Blair, dominated British politics for a generation, since he walked out of Downing Street with his wife Sarah and his boys John and Fraser five days after polling day.

"The boys had to leave as well," he says, explaining why his sons were cast into the limelight at such a sad time for the family. "They had to know we were leaving. They had to know that was it. That might have been their home but there was no going back. They were very good about it. Fraser skipped away."

He wonders how long it will take his boys to lose their London accents in their local school, but says they have settled in well. He has had the tougher task of coming to terms with being ousted from a job he coveted for so long. Defeat still hurts. In an interview to mark the publication of his book about the financial crisis that dominated his three-year premiership, he suggests history will be kinder to him than the voters were in May. And history is all it is now, he insists.

Brown is a voracious reader and his house overlooking the Firth of Forth in North Queensferry is stuffed full of books, but he says he has yet to flick through the memoirs of former cabinet colleagues that chronicle the power struggle at the top of the Labour government. Nor does he want to talk about Tony Blair, who blamed Labour's defeat on the abandonment of New Labour.

"I am not going to get into an argument with Tony or anybody else about the past. We are way beyond that. The public is not interested. They have had enough." Has he read the Blair memoirs? "No." How about Peter Mandelson's? "No. You have to live in the future, not the past." Doesn't he feel the urge to pen his own account of his decade as chancellor and almost three years as PM, just to set the record straight? "I am not interested in gossip. I am not saying 'never' but I am better concentrating on the things I am doing."

There has, though, been talk that Brown still has a big job left in him. His reputation, currently, is higher abroad than it is at home, and there has been speculation that he might pitch up at one of the big global institutions such as the International Monetary Fund or the World Bank. Will he still be the MP for Kirkcaldy and Cowdenbeath? "Let's wait and see. This is home."

And it is a home the former prime minister knows intimately. We drive around his constituency. "That's the farm where my grandfather was born," he says. He points out his primary school, his father's church, the house where he was brought up, the hospice where he and Sarah worked unpublicised in the summer of 2009, when the country was in recession and would-be assassins in the Labour party were agonising about whether to unsheathe their daggers.

He asks his driver to cruise down Kirkcaldy's charmless promenade so he can point out where Adam Smith developed his theory of free trade by watching the sailing ships slipping in and out of the Forth. On an impromptu walkabout with constituents, all of whom he appears to know, he points out the spot in the high street, next to a Greggs bakery, where Smith lived as he worked on The Wealth Of Nations.

Smith is one of the inspirations for Beyond The Crash, Brown's answer to what he calls the "first crisis of globalisation". While accepting there is a risk of countries becoming more protectionist in response to the crisis, Brown says the real solution is international cooperation for a global growth agenda. Swift action two years ago prevented a full-scale banking collapse, but he argues that needs to be followed by major reform of the global financial system and a range of different but coordinated measures in both rich and poor countries to boost growth and create jobs.

"We did the first stage, but the second and third stages have still to be done. The crisis is not over. We are in the midst of the biggest restructuring of the global economy that has ever taken place."

But isn't the problem that the moment for this big vision has been lost as countries seek to cut their budget deficits and protect their own markets? Didn't Britain turn its back on this in May?

Brown - with wife Sarah and sons - on the day he announced his resignation. Photograph: Stephen Simpson/Rex Features

"Let's see what happens," he says. "I was unable to persuade people that my economic policy for the future was the right one. People will judge by what happens over the next few years whether I was right. I am not going to be dogmatic but the policies I am proposing are far more comprehensive than those being pursued at the moment." He foresees problems in keeping down unemployment, "and what is the purpose of economic policy if not to make sure that people have jobs?"

Brown has sympathy for the students protesting against the government's decision to raise fees and cut maintenance allowances. "Of course I understand why they are doing it," he says. "Educational opportunity is the key to the future, yet 2,000 people were turned away from my local college, despite having the qualifications, because grant support is being cut."

As chancellor, he introduced educational maintenance allowances to provide financial help for those aged 16-18 in order to persuade them to stay on at school. These, to his anger, are now being cut. "I feel passionately that there should be no barrier to children staying on at school."

Brown is proud of the investment Labour made in health and education, bridling at the suggestion that the problem for Labour at the last election was that it had bought so heavily into free-market economics that it was hard to articulate a convincing argument for government intervention even after it was clear that only state action could save the banks from their own folly.

New Labour actively championed the City, worshipping the bankers and marketing London as a financial centre where the regulation would be light touch. Brown squirms when reminded of his last Mansion House speech as chancellor in June 2007, when he heaped praise on the City for leading Britain into a new golden age through its creativity, ingenuity and use of modern financial instruments, but says it was impossible to go it alone – on bankers' pay, on regulation or on tax – without putting the UK economy at a disadvantage.

"We did not know the true position of the banks," he says. "We knew that at the top of the cycle there is always a higher level of risk and that unless that risk was diversified, there would be a problem. But the assumption was that if one bank got into trouble, it wouldn't affect the whole system.

"A shadow banking system had arisen and the regulatory system did not pick that up. When we saw what was happening, we acted quickly."

In retrospect, Brown regrets not telling the public how close Britain came to financial lockdown in 2008, when the banks were within hours of being forced to shut their doors to their customers. "We should have told people how serious it was and how near the edge the whole system was. People have got the impression that we would have come through anyway, but there could have been a far bigger crisis."

Brown thinks banks are now running away from the principles of reform agreed at the G20 summits in London and Pittsburgh during 2009. "Unless we are more assertive about what the global financial rules are for the future, there will be another financial crisis of some sort."

After waiting for the premiership for 13 years after Blair pipped him to be Labour leader, Brown gives the impression that wearing the crown gave him little pleasure. Did he enjoy it? "We were dealing with very difficult times. You have got to accept that you are not going to do all the things you want to do."

So what's his biggest regret? "Losing the election," he says with an uncomfortable laugh. "I felt I had a duty to win and I didn't deliver."

He changes the subject in a way that is clumsily endearing yet explains why he sometimes had trouble communicating his heartfelt vision to the public. The conversation goes like this:

"Over there is a new eight-screen multiplex cinema I opened," he says, pointing across the countryside.

"Really. Do you go there?"

"Yes, we do."

"So what was the last film you saw there?"

Long pause in which Brown struggles to think of a film he might have seen in the past year. "The one about Mandela," he says at last. "Invictus."

Brown would probably have been more at home a century or more ago, when politics was about morality, principles and ideas, and politicians were not expected to bare their souls. He is certainly happier explaining how to sort out the problems of the European single currency, how the global economy can avoid foundering on the reef of protectionism, how bankers should live by an ethical code and how Labour can win the next election under Ed Miliband.

He is, he says, an optimist. "Other people have a pessimistic message. Every nation in the west is talking about national decline but it's not inevitable.

"We are witnessing the biggest shift in economic activity in our history. It is bigger than the Industrial Revolution. But we do not have to have protectionism. There is an alternative to people retreating into their shells, which is what is happening at the moment. But it is very difficult to explain to people." He says Barack Obama, given a bloody nose in the US midterm elections, is facing the same problem he had. "People feel insecure and they want answers to that insecurity."

His view now has greater traction given the crisis in Ireland and other parts of the eurozone, but it failed to resonate in the spring. "By the time of the election it was very difficult to tell that story. The debate was not focused on the global issues."

The decision of the Liberal Democrats to go into coalition with the Conservatives makes life easier for Labour, he says. "For a hundred years the Liberals have dined out on the idea that if they are given the votes they will be a progressive party. A lot of people voted Liberal thinking they were a progressive party, but now find the Liberals and the Conservatives in a rightwing coalition.

"The Labour party has a huge opportunity. The issue is how the Labour party can represent that progressive majority. Tony Blair and I never had that. Tony would say that as well as me."

Can Labour exploit that? "Of course. Ed Miliband is a great guy." But is he surprised that it is Miliband rather than Ed Balls, his other long-standing adviser, who succeeded him as Labour leader? "I knew that you were going to ask me that and I am not going to answer," he says.

Like Jim Callaghan, Brown inherited the premiership from a serial election winner, only to be booted out the first time he faced the electorate. So does he feel a failure? "That's for others to say," he stalls, but when reminded that Enoch Powell remarked that all political careers end in failure, he smiles and says: "It seems that way."

• Extracts from Gordon Brown's Beyond The Crash will appear in the Guardian on Monday 6 December and Tuesday 7 December. To read these online go to guardian.co.uk/politics/gordon-brown.

• This article was amended on Monday 13 December 2010. The subheading incorrectly stated that this was his first major interview since leaving office. This has been corrected.