For a man who missed becoming leader of his party because a few hundred votes were held up in the Christmas post, Chris Huhne is remarkably upbeat. He has just returned to Westminster after a trip to Beijing, and the bitter rivalry from his leadership contest with Nick Clegg nine months ago seems a distant memory.
Huhne, who has twice failed to become leader of the Liberal Democrats, was taking part in a programme to improve links between politicians and academics from Britain and China. Its name? The Leadership of the Future Forum.
Showing little sign of jet lag after the 10-hour flight, Huhne excitedly tells how a couple of days ago he was watched closely by three smartly dressed members of staff as he took an early-morning swim in the hotel pool in the Chinese capital.
"I was the only person in the water, and they just watched me swim up and down. I felt like Chairman Mao," he says.
The Lib Dem home affairs spokesman is the party's Gordon Brown to Nick Clegg's Tony Blair. He's older, smarter, more strategic and, probably, more ruthless. And it appears he still nurses an ambition to be leader.
Huhne and Clegg had a long friendship which has become strained as their political ambitions got in the way. They were both MEPs who arrived in Westminster at the 2005 election. But last December, in the second Lib Dem leadership contest within 20 months, the friendly rivalry turned to rancour. A member of Huhne's team described their opponent as "Calamity Clegg". Clegg eventually won by just 511 votes. But the gap between the closing date of the postal ballot and the announcement of the winner meant more than 1,000 votes came in late because of the backlog caused by the Christmas post – and most of them were for Huhne. After a secret meeting between the two men and senior officials, it was decided that the late votes should not be counted, and Clegg was declared the winner.
This is Huhne's first major newspaper interview since then, and when I ask about the late votes fiasco now, I detect a hint of regret – but he masks it with an open, broad smile.
"I have no idea about that. It's always been very..." he trails off.
Does he regret not calling for a recount?
"There was no question of a recount," he says, smiling. "I think the result was very clear and you have to have a date by which postal ballots are returned and you count the ones that are returned by that date and not the ones that are returned after it. And I have no doubt that Nick won fair and square on the rules."
But is there a small part of him that thinks if the leadership election had not been at Christmas, he would be addressing this week's conference as leader?
"There is a small part of me, when I see Nick haring off to do an annual dinner in Westmoreland in the dark and cold days of February, that says, 'Thank God I didn't get elected as leader'," Huhne replies, laughing out loud.
Clegg has just given an interview in which he admits that the public is "still getting to know me". How long is this going to take, I ask Huhne.
"In general, I think the leader of our party needs to go through an election to become a real figure in the front rooms of the country."
This conjures up an image of members of a family watching pictures of Clegg on their televisions, then giving each other blank looks. It doesn't sound very supportive.
Huhne adds: "Part of that process is actually getting to know the leader, and the leader being able to put across our point of view."
Huhne insists that he's loyal and that, by working with Clegg as a team, the Lib Dems are in a "much stronger" position – 18 per cent in the polls rather than the 13 per cent they held after Sir Menzies Campbell stood down last November.
But the Oxford-educated former economist and journalist, who once went out with an ex-girlfriend of Tony Blair's, doesn't seem the type to simply retreat into the background, so has he given up hope of becoming leader?
The smile is almost dazzling this time. "There is absolutely no vacancy," he says, adding quickly: "The thing that I care about most is making sure we as a party fulfil what I believe is our fundamental mission in British politics, which is to make this a country at peace with ourselves, through an electoral system and a political system that properly reflects all the various opinions within our nation.
"And that is something which I think people who are presenting our case do very effectively, and I think this coming election is an enormous opportunity for us."
This "enormous opportunity" could involve the Lib Dems becoming the power-brokers in a hung parliament – which electoral experts still claim is a likely outcome of the next election, despite polls predicting a Tory landslide.
Clegg has refused to discuss the issue, but Huhne is happy to set out conditions, including proportional representation and fixed-term parliaments.
"If the other parties are serious about co-operating in a multi-party system, then certain consequences flow from that. Can you be a partner in a coalition government where the prime minister can call an election at any time without consulting anyone in Cabinet?
"Let's say that the Lib Dems are in a coalition at the environment department, and the environment minister has just taken some pretty tough and unpopular decisions about tax and climate change. And the prime minister of another party decides this would be a good moment to ditch you as a minority party by holding an election."
As Huhne, the Lib Dems' former environment spokesman who pioneered the party's policy on green taxes, sketches out this hypothetical scenario, it's difficult not to imagine that he sees himself as the Lib Dem environment minister in a coalition government.
While Clegg is viewed as more sympathetic to Cameron, Huhne is so critical of the Tory leader during the interview that I suggest he would be more inclined towards taking a seat in a Labour-led cabinet, but he rejects this.
He says: "I am in politics as a Lib Dem first, and that's what I most care about, and I have no view as to whether Labour or the Conservatives are likely to give us more of what we're fighting for in terms of our programme."
Huhne sounds frustrated at the way a policy paper he published earlier this month was viewed by some as "soft on crime". It suggested giving those convicted of minor offences community sentences rather than jail, to free up space in prisons.
And he describes Cameron's call for automatic prison sentences for people caught carrying a knife as "completely barking".
He has long been a champion of Europe, but he reveals a significant shift in Lib Dem policy on the euro. After a decade, the party is no longer campaigning actively for entry into the single currency. This is surprising, coming from a man whom friends say was almost messianic about its benefits.
"There is enormous misunderstanding in this country about the successes of the euro. But the truth is that within the British debate it's completely off the radar, and therefore there is simply no point in regarding it as a runner worth investing political time in."
At their conference in Bournemouth, the new message will go out to activists that the Lib Dems are now a tax-cutting party, including the 4p reduction in income tax, from 20p in the pound to 16p. These policies on tax and Europe seem designed to prevent heavy losses to the Conservatives in seats in the South-west.
Huhne insists that the southern Lib Dems elected in 2005 will hold on because of an "incumbency bounce", while in the North they will take seats from Labour. Clegg's goal is to double the Westminster tally of 63 within two elections, but Huhne refuses to set targets.
But still, isn't the Lib Dem message getting drowned out by the resurgent Tories and Labour's infighting?
Huhne says Cameron cannot continue to "walk on water" in the eyes of the media for much longer.
Sitting for the photographer outside Portcullis House, Huhne, 54, checks his hair in a window. It's grey, but, as he points out, remains a full head of hair.
"Did you know that every man in Chinese politics, even when they are very old, dyes their hair black?" he asks.
The Chinese politicians he met at the Leadership of the Future Forum want John McCain to win the US presidency. Are they also captivated by Sarah Palin?
"Oh no," Huhne says with revulsion. "Sarah Palin is genuinely shocking. The idea that we should have somebody who is running the most powerful country on earth who believes in creationism and wants to make it compulsory in school deeply shocks me."
Huhne backs Barack Obama, adding: "One of the things that the US has in its past is slavery. And if the US was responsible for electing a black president it would be an act of redemption, which would, I think, be a very crucial bridge for many people."
To his counterparts in Beijing, Obama is too protectionist for the new free marketeers of China. McCain's appeal is based on the "residual respect for the elderly in Chinese society", he says. "They find a 72-year-old who's kicked around a bit on international affairs more of a reassuring figure than a 47-year-old who actually doesn't have any international experience".
It sounds as if they would like Ming Campbell, the 67-year-old who quit because he was fed up with questions over his age.
"That's probably right," he says, laughing.
The father of five, whose wife, Vicky Pryce, is an economist, made a lot of money on the right investments in the City in the 1990s and 10 years ago rated Beijing for the bond markets.
Famously, he has a considerable property portfolio – earning him the nickname, during the 2006 leadership contest, of "Nine Homes Huhne". When I ask about the nine houses, for the first time in the interview he cuts me off, sounding impatient.
"I don't, I have investments, actually – and not nine, it's seven. I have investments in five homes for rent, which is basically my pension fund from my time in the City; and we have two homes we actually use, which is one in Eastleigh and one in London."
So is he worried about falling property prices? No. He bought "for the long-term" when the properties were at the low point in the market last time.
I ask how the credit crunch is affecting him. It's perhaps unfair to ask this of a millionaire politician.
"It doesn't." He pauses. "If you mean the credit crunch in terms of availability of credit..."
Actually, I mean the general sense that we're staring into a recession, food and fuel prices are up, and homes are going into negative equity.
"Well, that's a different issue. It has an effect on the family budget as much as for anybody else.
"There are stresses and strains, but I don't claim that I'm in other than a very happy position compared with most people, because, having spent a bit of time in the City before I was elected, being able to make a bit of money while I was there, I have a cushion. And I also have a very hard-working and extremely intelligent wife, who manages to earn far more than I do."
No wonder he's smiling.
1954 Born in west London.
1967 Attends Westminster School.
1972 Certificate in French language and civilisation from the Sorbonne in Paris.
1975 Graduates from Magdalen College Oxford with BA in politics, philosophy and economics.
1977 Becomes UK's youngest staff foreign correspondent when 'The Economist' posts him to Brussels.
1983 A founder member of the Social Democratic Party (SDP), Huhne stands as a candidate for the SDP- Liberal Alliance in Reading East, but is unsuccessful.
1984 Marries Vicky Pryce, who is now chief economist at the DTI. They have five children and a property portfolio so extensive that it earns the MP the nickname "Nine Homes" Huhne.
1990 Wins the Wincott Award for Financial Journalist of the Year, after writing for both 'The Guardian' and 'The Independent on Sunday'.
1994 Founds a City firm, Sovereign Ratings, which scientifically measures the risks of investing in different countries.
1999 Elected to the European Parliament as a Liberal Democrat MEP for South-east England.
2005 Wins the Westminster seat of Eastleigh for the Lib Dems and within months is runner-up in the party's leadership contest after the resignation of Charles Kennedy in January 2006. Becomes environment spokesman in the reshuffle that follows Menzies Campbell's election as leader.
2007 Again runs for leader, this time just missing out to Nick Clegg. Currently the Liberal Democrats' spokesman for justice and home affairs.