The corridors of the heavily fortified Northern Ireland Office at Millbank in London boast a sophisticated alarm system. A sign at reception explains, “Flashing light denotes suspected hostile activity — consider countermeasures”. Perhaps the yellow warning signal should go off when the secretary of state himself walks in — for it is from these offices that Peter Hain is plotting for life after Tony Blair.

While the 56-year-old may not be engaged in overtly hostile activity, he is fighting a quiet guerrilla war to win himself John Prescott’s job after regime change next year. The cabinet minister, whose anti-apartheid crusading earned him the sobriquet Hain the Pain in the days when he waged war against South Africa’s all-white sports teams, believes that the job of deputy prime minister can be much more than the laughing stock that the present incumbent has made it.

“The only reason I am standing is not to get the prestigious position or any of that nonsense. That’s never interested me. The reason is that I feel very strongly and passionately that the Labour party has to renew itself at the moment. We have to listen more and lecture less,” he says.

So far, so ordinary — every senior Labour politician has been trotting out the same lines since the summer. But then Hain could be forgiven for failing to come up with a snappier job pitch: of late he has been devoting all his energies to restoring the Northern Ireland assembly after more than four years of political deadlock. The parties are on the brink of signing up to the historic St Andrews agreement and Hain believes power sharing at Stormont will soon become a reality again. On Thursday he will publish the legislation needed to begin the process of formally reopening the assembly, with full restoration of its powers on March 26 next year.

If it all comes off the prime minister will be thrilled: bringing a lasting peace to Northern Ireland would be a better legacy than the Iraq war and cash for honours. “There’s no question that Tony’s commitment to this agenda has been absolutely critical to making progress,” Hain says evenly. “He’s given more time and energy and sheer application than any prime minister before him. I think were it not for his own personal engagement we would not be where we are.”

If Hain is generous about who gets the plaudits it is probably because his mind is on life after Blair. He would like to see a new style of politics, he says, in which politicians give up their weasel words.

“It’s very important that we have a lot more plain speaking. We’ve got to rebuild trust,” he says.

He soon shows that he means what he says by launching into an unashamedly partisan assessment of the American elections last week.

“The Democrats are our sister party and so every Labour member got a real fillip out of the results and the Democrat victories — I certainly did,” he enthuses. “There is no question that the particular Republican administration in Washington is a right-wing administration. It is not our politics. Our politics align much more closely to the Democrats.”

Contrast these words with Blair’s and Gordon Brown’s diplomatic silence on the results. The government’s policy is not to wade into domestic US politics since President Bush is still in power. But Hain is only just getting going.

“There’s no question that George Bush is not the Labour party’s pin-up boy or, for that matter, the pin-up boy of most British voters,” he says.

He is not attacking the “special relationship”, he emphasises — it is “absolutely right” that there should be a “close partnership with whoever’s in power” in Washington. But he thinks that the Republicans have had their day and would like to see Hillary Clinton in the White House.

“When Hillary Clinton made her victory speech, which was a masterful speech, I thought, she talked about raising the minimum wage: tax reforms to benefit the many, not the few that Bush’s tax reforms have benefited. She talked about healthcare. These are Labour issues, so they obviously resonate with a Labour cabinet minister like me. I will be seeing Hillary in a few weeks’ time when I go to Capitol Hill to discuss the Northern Ireland process. I see her several times a year. She is an incredibly formidable politician. Her thumping victory has obviously given her a fantastic springboard for the future . . . It would be great to have a woman president in the USA.”