Following the handover of the Tube contractor to the client, TfL will be forced to examine with the government what changes must be made to the PPP system.
"Longer term, they will have to decide on what is best value for money, as Ruth Kelly has said on 7 November [to the Transport select committee]," Bolt said.
"My guess is that they [TfL] will look at a range of options – from re-tendering the PPP contracts, to a more radical option to take maintenance back in-house."
This could lead to the abolition of the PPP system of upgrading London Underground, forcing Tube Lines to surrender its contract to upgrade the Northern, Piccadilly and Jubilee lines.
A TfL spokesperson said: "The Mayor has said he would like to examine the possibility of bringing maintenance back in-house [and once contracts come under TfL control] we will re-structure the contracts, which will be done in the first months of next year."
Engineers have suggested that Bechtel may be called in to manage the underground, as London Underground lacks the engineering management resources and expertise (NCE 1 November 2007).
Bolt said he agreed with this assessment.
"If London Underground took the upgrades back in-house, then it would be something like Network Rail," he said.
"But it is the [private engineering companies] that have the asset and project-management experience."
Cutting out all private contractors could be problematic for TfL.
A Department for Transport spokesperson said: "We are working with the administrator, trying to find ways to transfer in the short and longer term. We feel there is a role for the private sector to be included in the longer term."