LONDON VAUXHALL DEALERS

Lord Coe, the man umbilically linked with a London Olympics that will begin in just five days' time, insists he is not losing any sleep despite a string of last-minute problems. As the clock in Trafalgar Square ticking down to the opening ceremony inches towards zero, he says he lives by the maxim of a Tory prime minister from the early part of the last century.

"I do slightly take the Arthur Balfour view of the world that few things matter very much and most things don't actually matter at all. Somewhere in between you always find the right balance," he says.

"Nobody in our organisation was sitting there thinking the final runup to the Games wouldn't be testing and that when planning collided with reality there wouldn't be fragilities."

Which is just as well, because the seven-year project has been marked by soaring highs and crushing lows – a pattern set early when an inspiring bid victory in Singapore was followed a day later by the 7/7 bombings in London.

The last week or so, with the Olympic Park finally open to the world's media, athletes and officials, who began streaming into soggy Heathrow, has represented one of the most testing periods of all.

Questions were asked in the House of Commons and the troops called in following the admission by the security firm G4S that it could not provide its share of 23,700 guards within Olympic venues.

Coe, a gold medallist in 1980 and 1984, is clear where culpability lies – and it's not with his organising committee. He insists there is no correlation between the decision to increase the number of guards within venues from 10,000 to 23,700 – necessitating a fivefold increase in G4S guards – last December and the recent scramble to fill security rosters.

"This company is four times bigger than any other security company in the world. We were assured they could do what they were being asked to do when we made the final assessment of security needs once we knew the sessions and the venues," he says.

With all parties keen to draw a line and move on, Coe stresses that security has not been compromised by the saga.

Asked whether he feels let down by G4S, Coe says: "I'm not remotely dodging the question, but I'm not very good at letting anger, frustration, emotional response get in the way of this. We had a problem and we identified it at the beginning of July. We acted within hours of really understanding that this was a big issue. The point which has been slightly lost is that I know we have the numbers. We have the numbers because we have the military and eight police services here."

As it is, the presence of those troops and police officers will probably end up having a positive impact on perceptions of the Games, he says. "There is a big affection for their presence and they are really smart, engaging people. Their ability to deliver a safe and secure Games is not high on my list of concerns."

On Friday, the curtain will come up on a 17-day sporting celebration that will host 8.8 million ticket-holders, 10,500 athletes and twice as many members of the world's media. The government is selling it as an investment in the future, promising a legacy for everything from tourism to inward investment. Others remain more sceptical, but most are looking forward to the sporting spectacle.

Coe is hard to ruffle. But even he has appeared slightly unnerved in recent weeks. He had spoken recently to two contemporary athletes who had "fallen at the final hurdle" for selection and sympathised with their guilt at letting others down.

"There is a large chunk of me that says I don't – and we don't – want to let people in this country down. We're as excited about doing this. The 6,000 people in our organisation have lived and breathed and slept this. Of course, we feel a massive responsibility to get this right."

It will be "interesting", he says, to compare the feeling 40 minutes before Danny Boyle's £27m opening ceremony – described as a creative "high wire act" by those who have seen it – and his pre-race thoughts as a competitor.

"You learn a lot about yourself in those 40 minutes," he says, munching on pasta from the media canteen.

"I do accept, though, that was very individual. It was about not letting your nearest and dearest down. It will be the same sort of feeling, just multiply that by a lot more people that you don't want to let down."

The London 2012 organising committee, which is staging the Games using a privately raised £2bn budget but also benefits from more than £800m from £9.3bn in public funding, is a strange beast. It starts small and raises hundreds of millions in sponsorship, grows furiously in its final two years, then abruptly dismantles itself and flogs off its assets.

Coe's organising committee has benefited from the work of the Olympic Delivery Authority in building the gleaming venues and transforming a toxic wasteland into an impressive new urban park ahead of time and under budget.

That gave Locog some wriggle room, but it has since faced searching questions over the ticketing process, security and a perceived lack of transparency. In the plus column, the torch relay has been something of a triumph, more than 8m tickets have been sold, and the IOC and athletes are happy. Coe is proud, he says, to have put sport at the heart of the political agenda.

"My whole life, if there's been one continuum through pretty much everything I've done, or said, or roles and responsibilities I've had since the age of 18, it has been to secure a more robust and permanent place for sport in the political and social agenda."

The 55-year-old says the legacy promises that secured the Games have provided a "road map" to hold others to as economic times have got tougher, but accepts that delivering on them after the Olympics will require real political will.

Coe has permitted himself one or two moments of satisfaction, such as when he visited the Olympic Park with British IOC member Sir Craig Reedie so that they could share a Field of Dreams moment.

"We stopped the car and got out and had our little moment and then got back in and continued. But you don't dwell for very long as your mobile goes and there's another conversation to be had," he says.

Yet he retains an unshakeable conviction that the Games will be a triumph. He says he is not surprised the torch relay that arrived in London this weekend has been such a hit around the country, reaching an estimated 10m people. Coe believes it will go "up a notch" again this week in the capital.

For all the last-minute concerns, which have led to articles in the foreign press characterising us as a nation of whingers, Coe believes the Games will showcase the best of Britain – on the field of play and off.

"We were never going to win the bid, we were never going to be able to build it, then we weren't going to be able to raise enough money, then we weren't going to get any volunteers, then the torch wasn't going to ignite the excitement, then we didn't have any athletes — which we put behind us by Beijing. Then it was going to be chaos and it hasn't been," he says.

"We have a great, endearing ability in this country to question our ability. Often, it's quite counter-cultural. We have large parts of Britain in leading edge niche markets around the world, we have some of the most extraordinarily creative people ever put on this planet with a history and tradition that the rest of the world looks on enviously if a bit curiously. I like to think that with odd ups and downs we've shown that when we do things properly and we do things collegiately, we do them as well as anyone in the world."

As for London, he hopes that by the time the curtain comes down on the Paralympics in September it will be seen globally as "a modern, confident – not brash – city at ease in its own skin".

Coe has been selling these Games and their benefits since he became bid leader in 2004, but one telling aside when considering the range of perspectives from which he has seen the various Olympics since Moscow in 1980 reveals that even he recognises this is a leap into the unknown: "It will be interesting. We haven't done this before."