The government has insisted that the private sector must carry the risk of completing the work of failed London Underground maintenance company Metronet.
This is despite the fact that public body Transport for London is the only bidder to take on the contracts.
A spokesperson for the Department for Transport said: “The risk must be with the private sector. In the short term the contract will be in the public sector but in the long term we have to see private involvement.”
If successful in its bid TfL will take over responsibility for the daily maintenance of track and trains, while the private sector would assist in upgrading the lines and stations.
There has also been a debate about the legality of allowing TfL to take over the contract as the GLA Act states that the contract must be with a private firm.
A select committee hearing on Metronet was due to take place as Building went to press.