Motorists faced long queues on routes where pre-Olympics modifications have been made to road layouts on Tuesday.

There were delays of up to an hour on the A13 between the Canning Town Flyover and the A1261 East India Dock Link Tunnel junction in east London.

There were also jams on the A12 southbound in Leyton in east London while there were 45-minute hold-ups on the A40 Western Avenue in west London.

The delays were less severe at these spots than they had been on Monday, suggesting that drivers were heeding the warnings by Transport for London (TfL) to avoid driving in London in the run-up to, and during, the Games.

The road changes have been made ahead of the full introduction tomorrow of 30 miles of Olympic traffic-only Games Lanes in London as part of the 109-mile Olympic Route Network.

Also, London Underground services were running without delays on Tuesday, but Monday saw a series of problems, including routes that will serve the Olympic site at Stratford in east London.

central line

The Central Line was heavily delayed on Monday after a track fault rerouted thousands of commuters

These included the suspension of the Central line between White City and Liverpool Street due to a fault on the track near St Paul's.

Also last night, faulty track at Hackney Wick led to severe delays on London Overground services between Canonbury and Stratford.

Bob Crow, general secretary of the RMT transport union said his union had warned that "a combination of maintenance and staffing cuts would leave the Olympics' transport plan as nothing more than a wing and a prayer".

He went on: "The past hours of total chaos is proof positive that we were right."

Meanwhle, Heathrow airport was having its busiest day for Olympics arrivals today, with around 1,200 athletes and coaches flying into the west London airport as well as more than 3,000 other Games-related arrivals.

In total, Heathrow was handling around 217,000 passengers today, including 99,000 arrivals.

Immigration queues for arriving passengers at Heathrow were reported to be moving smoothly