According to a report in the Times today, Transport for London, which is controlled by London’s Mayor, will shortly agree a deal with Tube Lines owners Amey and Bechtel.

The move would send the £30bn Public Private Partnership hurtling into the buffers and mean that Tube Line’s 3,000 staff will be reunited with the 5,000 former Metronet staff, who now work directly for London Underground.

Discussions have been continuing over the past couple of weeks between Tube Lines and TfL but could not be finalised until the election was over.

The deal marks the end a bitter dispute about the scope and cost of the Tube modernisation.

Tube Lines had proposed to charge TfL £4.4 billion for the next phase of maintenance and upgrade work on the three Underground lines. But TfL has argued that the true cost should be only £4 billion.

Last month the projector arbiter, who oversees the London Underground Public-Private-Partnership agreement, told TfL to scale back its ambitious upgrade plans or stump up more cash.

The arbiter’s ruling that Tube Lines could not raise the money itself is understood to have triggered a provision in the complicated PPP contracts that enables the shareholders to sell to TfL and receive compensation.

The Mayor has previously claimed that Ferrovial, Amey’s parent, and Bechtel, stood to get £400m in management fees by 2017.

According to the report, a TfL spokesman said: “TfL continues to work closely with Tube Lines and its shareholders, Amey and Bechtel, to explore all options to address the issues outlined by the PPP Arbiter.

“The parties are yet to reach any conclusion, but we remain committed to working with Tube Lines and its shareholders to identify the best way of providing the vital improvements the Tube needs.”