LONDON: Utter chaos prevailed on London’s streets on Monday as athletes started arriving for the upcoming Olympics, with a 51km long traffic jam hitting traffic and logistic problems forcing some of them to take an unintentional ‘tour’ of the city.

The Olympics are set to begin from July 27 and the period is being described as Britain’s biggest peacetime transport challenge, as contingents from 50 countries camp in the city. A 51km long traffic jam on an arterial motorway into London was reported as special lanes and vehicles transporting athletes and officials came into operation on Monday, affecting normal traffic.

The first of the teams — Russia, Australia, Italy, China — arrived amidst reports that many athletes and officials had to make circuitous routes around London because untrained bus drivers lost their way en route to the Olympic Park in Stratford.

Two buses containing Americans and Australians were reportedly lost, one for four hours, the other three hours this morning, even though their route was supposed to be fast-tracked by the implementation of the Olympic lane on the M4 motorway.

As the Daily Telegraph termed it ‘London 2012 Olympics travel chaos’ , a spokeswoman for the organizing committee said: “We will do over 100 bus journeys today. It is day one and we have only had one or two issues where journeys have taken longer than planned. The vast majority of journeys have been fine.”

Hugh Robertson, the sports and olympics minister, apologized to athletes who were caught up in the transport problems. London mayor Boris Johnson made light of the road problems by saying: “If they (athletes, officials) took four hours then they will have seen far more of the city than they might otherwise have done.” Heathrow was expecting to process as many as 236,955 passengers on Monday , which would surpass its previous record of 233,562 set on July 31 last year.