"My mother said to me that if I passed my exams and went to university I wouldn't have to work nights!" Neil Kinnock declares, with half a broad grin. "One way or another I have been working bloody nights ever since and I am an old man now."

There is a hint of darkness, these days, in Kinnock's exuberant humour. He looks fresh and trim, fitter than during the gloomy days and nights when he led the Labour Party, but the interview is peppered with references to his age. The engaging wit that was a trademark of the youthful Kinnock has returned, but now he is 57. What is more, the older Kinnock is embarking on a challenge that reminds him of the one he faced in September 1983. Sixteen years ago his task was to make Labour electable. Implicit in his new brief is the seemingly impossible task of making the EU acceptable to sceptics in Britain. Kinnock is in charge of modernising the Commission, an institution arguably as out of touch as Labour was in 1983.

"When I was asked to do the job I did think of the parallels. But there is a big difference. In 1983 I didn't know any better. Now I'm a thousand years older and I do know better. There are some jobs you are asked to do and you can't say 'No', because if you did you'd have trouble shaving for the rest of your life. I've always preached the importance of modernisation and good governance. I had to do it."

Even so he is not exactly jumping with joy. Some newspapers in Britain portray his life in Brussels as one long, lucrative holiday. As we settle down to coffee at the Commission's London office, I ask him directly if he's enjoying himself in Brussels. There's a long pause. "Enjoying myself? Sadomasochism has never been one of my pleasures. There's a degree of enjoyment as we get things done, but the more successful we are in carrying out administrative reforms, the less anyone will know about it. There's only a fuss when things go badly wrong. Maybe in four or five years' time people will start to say that the Commission is functioning better. But as we get to that point, there are no conference speeches, or triumphs in resolutions, or bills blocked and bills passed."

Kinnock would not go as far as to suggest that he misses those never-ending meetings in which party resolutions were fought over. Nor, I suspect, does he miss the preparations for the leader's speech at the party conference. (I watched Tony Blair's speech at this year's party conference sitting next to Glenys Kinnock. As Blair left the stage at the end, she said to me: "He'll walk off and say, 'Thank God that's over for another year'. Neil always did.")

Still, Kinnock keeps an increasingly eager eye on domestic politics and, I suspect, feels deeply ambiguous about being an exile now that Labour is in power. He speaks regularly to old colleagues who have become ministers and has strong views on the Blair government, most of which he expresses only in private.

But on one domestic issue he is adopting a high public profile. Labour's internal contest to select a mayoral candidate has brought out the old campaigning Kinnock. He is determined, first and foremost, that Ken Livingstone should not become Labour's official candidate. Second, he wants Frank Dobson - "A good mate for at least 20 years" - to win the ballot of party members. Evidently he detests Livingstone.

"Ken has been much more a member of the Livingstone party than the Labour Party. London is more a place for performance for Ken, not a huge challenge. That was evident at the GLC, pathetically so. But what matters now is the future. He wants to raise taxes that he wouldn't have the legal powers to raise and to borrow money that he wouldn't have the legal powers to borrow . . . and to sack Gordon Brown. That's his economic policy."

But is he not, at least, a charming and formidable political performer? "Charming? No. Ken's a card and you've only got to read Arnold Bennett to know how far they get. People tell me he'll improve when he gets the job, but I don't think the mayor of London is the place for on-the-job training."

Kinnock deploys an intriguing term to describe Dobson, suggesting that Blair's favourite adjective is out of favour with him. "Frank is 'real Labour'. He's totally dedicated to London, has bags of imagination, humour and realism."

Kinnock has always been wary of criticising Blair publicly. Yet he does so implicitly when he talks about the handling of Livingstone. I ask him whether he would have blocked Livingstone had he been in Blair's position. There's another long pause. "Let's put it this way. I think I would have started the argument much longer ago."

Kinnock is far more forgiving about another of his sparring partners from the eighties - John Prescott. He is sympathetic about the Deputy Prime Minister's current plight. "We had our clashes for sure, but he's still very much a friend. I don't think John has capitalised on the fact that he's been interested in transport for decades. When he was my transport spokesman he came up with initiatives that demonstrated just how far short the Tory regime was falling. If anybody could tell the country what the workable transport agenda was and that there were no instant answers then it was Prescott, but he's on one hell of a steep hill now."

He believes transport should be right at the top of the government's agenda. "With transport, when it works most other things work; when it doesn't, nothing does. But there are no quick answers in transport, just none."

For Kinnock, as he seeks to modernise the institutions of the European Union, there are no quick answers, either. He remains optimistic - but does not hide the level of resistance within the EU.

"There are some, a tiny number, who are against change of any description. As I once said of some Labour Party members, they've got 'Do not disturb' notices on their minds. Second, there's a group that believes genuinely, but wrongly, that reform is an attack on their history and dignity. They will say that this system drove Europe forward, this system was shaped by the founding fathers. I say to them, let us revere the history and let us show the same vision that they showed then."

Kinnock is overseeing what he calls "organic" change. "We're introducing new training schemes, a more effective promotion system within the bureaucracy. There is now a strong emphasis on merit as a precondition for top appointments, while taking into account geographical balance. In many cases in the past the flag came first. Now we're putting the flag in its proper perspective."

Confirmation that merit has not been the main criterion for filling the top jobs, along with Kinnock's view that the Commission's system of financial auditing "has not changed since the fifties", will be music to Eurosceptics' ears. He is trying to change the tunes. "This is a money-handling institution and, therefore, by changing the financial management, you change all the other structures and the ethos itself."

Does he accept that the urgent need for reform is a vindication of sorts for the sceptics?

"I take notice of those who have argued consistently for the modernisation of the EU, but so many of the sceptics in Britain are just hostile to the whole European idea."

Unlike some of his fellow commissioners, Kinnock comes from what he calls the "rougher end of the trade. Others in mainland Europe have been political activists when young, got on party lists, demonstrated proficiency as ministers, became distinguished in their countries, but it was a less tortured experience."

He still shows signs of the torture, as when I ask him whether, during his lower moments in charge of his party, he believed that the century would end with a Labour government? "Oh those low moments! All the time you have to display such patience in opposition. My patience was stretched to bow-string tautness from time to time. I did envisage a Labour government, but that majority is pretty impressive I must say."

He argues that governing demands patience. "On one side of the equation there's the power, and it is monumental power. On the other side, there are the wounds of 18 years to be healed. Everyone from the top of the party - and I mean the very top - spends a bit of each day saying, 'Let's move faster, let's just do it'. But we must all recognise that the reforms will be stronger and deeper rooted if they are implemented with great deliberation. That's a stronger test of patience than anything I experienced in opposition."

In the months following his resignation in 1992 Kinnock was highly critical of his own leadership. I wonder if he now views those nine years as the necessary prelude to the landslide? He looks uncomfortable: "No. If I was to do that I would be running away. So I don't do it."

Does he not see, in any way, the 1997 win as vindication for his earlier reforms? "We lost two elections under my leadership. If I don't blame myself I would go around blaming everyone else, and that would be silly."

There is one area of policy, above all others, that would have brought him satisfaction. "The one thing I would have absolutely craved would have been the restoration of normality in Northern Ireland. People who knew me ten to 12 years ago would know that this was a big passion, up there with unemployment. The risk-taking, doggedness, cajoling have been remarkable and the result is extraordinary. I was on the Shankhill Road recently and you feel and taste the difference."

As he is the last New Statesman interviewee of the century, I ask him to select his political hero from the past hundred years. "Very subjectively, it would be Nye Bevan, but circumstances, including his early death, meant that he couldn't be the figure for the century. I would have to say Nelson Mandela. His gifts for doggedness, vision and forgiveness are superhuman. He's also got a sense of humour, which you don't always associate with these secular saints!"

As I leave, Kinnock revives one other moment from the 20th century. "I started reading the NS in 1955 in the school library. We've been subscribers since the sixties, but I remember going into the library and picking it up for the first time. I was 13 in 1955, which means I'm bloody ancient now."