But retendering design contracts for Crossrail is not expected to cause a delay to the scheme, senior Crossrail advisor Steve Rowsell claimed this week.
Multi Disciplinary Consultant (MDC) contracts could be re-bid because their scope is being extended following contractors' rejection of design and build procurement (NCE 18 October).
"A final decision on the scope of the final organisation needs to be agreed before Royal Assent next year," said Rowsell.
"There are no final decisions at the moment. The overall requirements are being looked at."
Speaking at NCE's Civils 2007 conference last month, Crossrail executive chairman Doug Oakervee said a method dubbed Optimised Contractor Involvement (OCI) was the most likely construction procurement tool for the £16bn project.
"You have to look at it in the context of a delivery strategy. Detailed design has to be undertaken – how much design has to be done before you let the construction contracts? We are doing more design in-house to ensure project-wide consistency. How much involvement do you want from contractors?, said Rowsell.
The Crossrail Bill could gain Royal Assent as early as summer 2008, leaving Crossrail around six months to finalise the final project team and complete detailed design work.
Four Multi-Disciplinary Consultancy (MDC) contracts have so far been let – to an Arup/Atkins joint venture, Halcrow, Mott McDonald and Scott Wilson. A fifth contract to Bechtel is due to end in 2008.