Iam joining Jack McConnell on his battle bus at the crucial halfway point of the most critical Scottish election campaign Labour has fought. It’s a very nice bus — spotlessly clean, tastefully liveried, high-tech . . . and almost empty.

Election campaigns are analogous with circuses for good reason and not just because politicians are apt to make clowns of themselves. Even Donald Dewar trailed Spice Girl lookalikes, balloon-wielding students, sinister-looking men with ear-pieces, fresh-faced interns, a stylist and a couple of burly Special Branch minders in his electioneering wake.

Aboard McConnell’s bus are his spin doctor, a PA, two newspaper photographers, the leader of Glasgow city council, the man from the Evening Times and me. You could fit us all in the back of a Volkswagen Touran and still have space for a small dog. There is not so much as a sticker, let alone a rosette, to give a hint as to what our mission is. Nobody hands out election leaflets because there aren’t any. Labour’s 2007 election campaign is so low-key it is in danger of disappearing off the radar.

McConnell bounds on to the bus. He is wearing a blue suit and a swirly pink tie, but minus the red rose buttonhole beloved of Labour candidates. He could be middle management or a member of the rotary. He’s affectionate — a kiss on the cheek for me, conspiratorial gossip for the man from the Evening Times. He doesn’t hide himself up the back with a huddle of advisers but plomps down among us.

The last time I interviewed him was in 2000. Then there was an edge to him, a whiff of sexual danger, even, and a hunger for supremacy. Now he is cuddly Jack. The days of his spin doctors whipping pretty young nurses out of photo opportunities — mindful of the sexual peccadillo that led him to launch his premiership by admitting an affair — are long gone. Now he can joke about the pensioners at the Knights-wood community centre telling him he is better looking than on the telly and if only they were younger.

He talks about the SNP “shadow boxing” and their unwillingness to engage. “They’re hiding,” he says. He seems nervous and looks as if he believes this as little as I do. The SNP leader’s smug mug is everywhere. Independence is on everybody’s lips. He visibly relaxes when we stop talking politics. Later, at Abercorn school, he admits to the children that first minister’s question time makes him nervous. He is more honest than people give him credit for. He’s nicer, too.

Our first stop is Partick library for a “bounce and rhyme” toddler group. McConnell is at his best in this setting — tactile and relaxed, unobtrusively stroking the babies while talking to their mothers. It’s the instinct of somebody who is a natural with children. “My kids are very important to me,” he tells me later. “They changed my life when I adopted them. It was the best thing I ever did.”

It’s telling, though, that nobody has thought to bring any Labour stickers or balloons. While the internal debate has raged over the merits and demerits of negative campaigning or how much London should pull the strings, some basic elements have been overlooked — the story of McConnell’s premiership, perhaps.

Wendy Alexander, the former “minister for everything” bounds over with Michael, one of her 14-month-old twins. This is her local group. She is one of the politicians — along with Andy Kerr, the health minister, and Margaret Curran, the parliamentary business minister — tipped to succeed McConnell. She admits that “people are a bit scunnered with us” but believes the potential cost of independence is beginning to filter through.

The analogy Alexander and McConnell make is with the 1992 Westminster election when John Major took the lead in the final fortnight. “At this stage in the campaign, Major hadn’t even brought out his soapbox,” says McConnell. But the flaw in the analogy is that 1992 was the Conservatives’ final fling with power - the dead cat bounce of British politics. It’s hardly an auspicious comparison.

Over pâté and oatcakes in the Red Onion around the corner from Labour’s Glasgow headquarters, McConnell is eager to defend his record. “It’s a funny election campaign,” he says. “Almost everybody would accept that the country is a better place than it was when I became first minister and that I’ve made a difference, yet we’re behind in the polls”.

The question is, has he made a big enough difference? Ask him to define the essence of “McConnellism” and he talks about his passion and positive attitude. “I find observing disadvantage painful and quite emotional. I’ve dedicated my life to eradicating it.” Pinning him down to specifics is more difficult. He highlights the smoking ban and his campaign against sectarianism. It seems too slight a legacy for five and a half years in power.

How does he account for the SNP’s remarkable revival? After all, if anyone understands their appeal it is McConnell, who flirted with nationalism in his youth. “After 10 years there is a bit of a mood for change,” he says. So Alexander is right when she talks about people being “scunnered” with Labour? “There is a bit of that,” he says. “I think people are not yet seeing the Scottish parliament as decisive in their lives. They think it is possible to have a protest vote in the Scottish election without there being consequences. It will change your tax, it will change the economy and it will change the atmosphere in our country if these people win.”

The suggestion that the Scottish parliament has failed to make an impact on people’s lives seems a damning indictment of his time in office.

“After eight years it’s become such an accepted part of our national life,” he says of Holyrood. “Opinion surveys show that people believe Westminster can second-guess Holyrood, that if the Scottish parliament gets it wrong, Gordon Brown or Tony Blair can fix it and that isn’t the case.”

The SNP’s rating in the polls would suggest, however, that people believe the powers of the Scottish parliament to be limited and have decided they want the executive to be able to deliver more. McConnell refuses to take the swell of support for independence at face value.

“When the UK government is a bit unpopular, the question: ‘Would you like powers transferred from the UK government to the Scottish parliament?’ is a bit of a no-brainer,” he says. “But if you say: ‘Would you like your taxes set in the Scottish parliament? Do you want immigration decided in the Scottish parliament? Do you want the defence of the country to be in the hands of the Scottish parliament?’ It’s a very different set of questions.”

Promoting Holyrood’s limitations seems an odd way of defending the Union. “It’s difficult to communicate that the current settlement is flexible, that we’ve transferred real powers,” he says. “I have no doubt there will be other powers transferred in the next four years.”

Such as? “There are all sorts of areas that are the subject of discussion in white papers and so on. There is a discussion to be had about how best to tackle climate change both at the UK and the Scottish level and that might result in minor adjustments to the settlement. But it shouldn’t be a point of principle that it has to happen.”

How does he answer the charge he underestimated the threat from the nation-alists? “I didn’t underestimate them,” he says, stressing “I” and giving the impression others did. “I was absolutely certain this was going to be a tough election. But it’s difficult to campaign in advance of an election when you are in government. Since last September I’ve been laying out the vision for the next four years.”

The criticism that Labour has been too slow to defend the Union have stuck, however, and McConnell can only fight his ground with “I certainly don’t think you can say that now”. He has also been accused of failing to distance Scottish Labour from the wider Labour problems of Iraq and Blair’s unpopularity. Will the breakdown in Iraq be paid for by the break-up of Britain?

“If people use this election to protest about Tony Blair they will be living with the consequences of that decision for decades,” he warns. “There are many people in Scotland who would never forgive themselves if they were to make a mistake on May 3 and then realise the scale of that mistake. None of us who know Alex Salmond believe he will do anything but spend the first three years securing a ‘yes’ vote in a referendum and building on every grievance. The impact of that will be uncertainty and insecurity. The referendum is like a train coming down the track and after May 3, if people vote for it, they will be tied to the track.”

McConnell is likely to go down in history as the politician who squandered the huge advantage Labour had in Scotland. That must keep him awake at night. “The people who should be worried about that are the Tories and the Lib Dems, who have become so marginalised in Scottish politics,” he says. “I don’t do this job for the good of my health.”

He didn’t enjoy his first 18 months in office. “I found it very difficult,” he says. “I wasn’t expecting Henry [McLeish] to resign.” Was he ready for the office of first minister? Would it have been better to wait five years? It’s a suggestion he denies. “I really enjoy this now. The successful Scotland that I see is partly my creation. That keeps me going when it gets hard.”

But there are “aspects of family time” he misses. The job is unrelenting. He doesn’t see his wife Bridget as much as he would like. He last played golf in October. Socialising is well nigh impossible. He gets back to his home island of Arran “not enough — once every couple of months”.

“I still love it over there,” he says. “It’s so relaxing. I miss my family. They feel particularly the relentless day-to-day scrutiny this job attracts. I’m certain my mother does. It has an impact on my parents.” Can he talk to them about it? “A bit,” he says. “They are very protective. They look for the good news. They say: ‘I liked your second answer to first minister’s questions.’ ” His dad is 70 next week and while he won’t get over for the birthday party, he’s taken time out to organise a personal surprise present.

“Five and a half years is a long time to be in this type of job,” he admits. “If you look across Europe, both to devolved leaders and national leaders, it is a long time. But when I think like that, I think about the things I still want to do. I come from a farming family, where people have had to work hard for a living, irregular hours, seven days a week. Do I get that from my father? Some people think I do.”

He denies the rumours, emanating from his close circle recently, that he’s had enough and is fed up taking the flak. “Rubbish,” he says. “No truth at all. I’ve never been in any doubt that I wanted a third term.”

If the polls are to be believed he is unlikely to be first minister after May 3. He’s only 46. What will he do with the rest of his life? “At the moment I’m focused on the next four years,” he says. “Whatever I do in my life I’ll do something that helps teenagers and young people. That’s where my interests lie.”

McConnell takes heart from the warmth people show him on the doorstep. Workmen shake his hand. Passers-by are genuinely friendly. Few argue politics with him. But ask them if they’ll vote for McConnell and they’re not sure. It’s as if they already know he is on his way out. It feels more like a valedictory tour than an election campaign.

McConnell may indeed be a man fighting for his political life, but he’s doing so with one eye on his political obituary.

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