LONDON'S £10BN Crossrail project could face a five-year delay because of the 2012 Olympic Games, the departing head of the project promoter said last month.
Outgoing chief executive of Cross London Rail Links, Norman Haste, doubts whether the two projects could be built at the same time.
At the second reading of the Crossrail bill last month, transport secretary Alistair Darling announced that government consultation on funding of the project has been delayed until 2006.
Construction of the principal Crossrail tunnel between Paddington and Stratford is scheduled to start in 2008 and complete by 2013.
This would clash with the £2.7bn programme to transform Stratford and the Lower Lea Valley into London's Olympic Park.
Speaking before the bill's second reading, Haste called for serious debate on whether Crossrail should be delayed until after the Games.
'The idea of Crossrail moving at a slower pace is worth consideringà a debate has to be had, ' he said.
Haste fears the two sites are too close together and that the sheer volume of work would escalate costs.
'The strain put on the core skills needed for both projects is something that is going to have to be looked at very carefully.
'It's na´ve to think it will not put up construction costs, ' he said.
A spokesman for Cross London Rail Links conceded doing both projects in parallel would be 'challenging but not insurmountable'.
'This is a time for London to be bold, ' he said.
Stephen Glaister, professor of transport infrastructure at Imperial College and a board member of Transport for London, agreed costs could soar if both projects are attempted simultaneously.
'Construction costs are already going up very fast and the Olympic work is bound to accelerate them, ' he said.
Arup director Peter Head questioned Crossrail's funding. 'I don't think the money can be raised from Londoners for Crossrail and the Olympics, ' he said.