THIS week some will see London as never before: free-flowing traffic, not a roadwork in sight and lampposts adorned with brightly coloured flags promoting the city.

This Utopian vision of the capital will last for one week only. It is being put on for 13 VIPs from the International Olympic Committee (IOC) who are arriving at Heathrow tomorrow night.

London commuters are likely to face more delays as traffic light sequences are altered to speed the visitors across the city. The dream of hosting the 2012 Olympics, which has cost £30 million to date, is in the balance. The committee is here for a four-day technical assessment of the proposal, which will be presented to the rest of the 117-strong voting IOC members before the final decision in Singapore on July 6.

Paris remains the favourite to host the Games and will be visited last by the evaluation team. London is second on the IOC’s evaluation tour after Madrid and before New York.

Even if this week’s assessment sings London’s praises, victory is still far from assured. But if the technical report throws up any serious problems, the bid is dead and with it the hope of the East End’s regeneration and promises of better transport for the capital.

The stakes are high, so the preparation has been meticulous. Only the weather has been left to chance, and even that looks good: sunny skies are predicted.

The IOC delegation, led by Nawal El Moutawakel, the first Muslim woman to win an Olympic medal, will be staying at the Four Seasons in Canary Wharf, where rooms cost from £330 a night. The committee will spend most of the time receiving 17 presentations on the themes of the London bid. These will be made by Sir Ian Blair, the Metropolitan Police Commissioner, Sir Liam Donaldson, the Chief Medical Officer, Jonathan Porritt, the environmentalist, and Sir Martin Sorrell, the advertising guru.

Most nights, the commission will be busy poring over London’s bid document during working dinners. On Friday they will dine at Buckingham Palace, where the Princess Royal, one of Britain’s three members of the IOC, will join the Queen. Another vital aspect of the IOC trip will be the visits to the proposed venues such as Wembley, Lord’s and Wimbledon. In the interim assessment last May, the IOC said that “urban expressways and main arterial road facilities lacked the capacity to provide reasonable travel times” and that claims of average bus speeds of 35mph “appear unrealistic”.

In response, Transport for London has mounted a huge operation to try to ensure things go smoothly. It has 16 traffic control engineers carrying out “health checks” at 337 points along the Olympic route network. A network of wireless CCTV cameras has been installed across London by a private contractor to monitor the IOC visit. These will even be positioned in Oxford Street to monitor the flow of buses, should the team decide to visit the shopping district.

Newham Council has built an Olympic-themed ice rink outside Stratford station. A bid representative told the council that a reason was that Gilbert Felli of Switzerland, one of the IOC members, is a former ice-hockey player and has organised figure-skating championships. Another inspector is Sam Ramsamy, a veteran of the anti-apartheid movement and a friend of Richard Caborn, the Sports Minister.

Lord Coe, the head of London 2012, is cautiously confident. “People who watch this closely on a day-to-day basis think we have narrowed the gap quite dramatically in the last few months,” he said. “But I think it is too close to call.”

Transport for London said: “No other road users will be adversely affected as a direct result of the IOC evaluation commission visit.”