LONDON UNDERGROUND has issued the first emergency direction to a contractor since the Tube’s part-privatisation two years ago, prompting fears that Ken Livingstone is trying to undermine the £30 billion Public Private Partnership.

London Underground (LU), which is controlled by the London Mayor’s Transport for London, has sent its own inspectors into two train depots after poor maintenance caused an emergency braking sytem to fail four times in the past month.

The unprecedented move has caused concern among the Tube’s PPP contractors, Tube Lines and Metronet, that Mr Livingstone will exploit safety-related incidents to sabotage their 30-year contracts.

A spokesman for LU said that Tube Lines, which was subject to the emergency direction, could be stripped of its 30-year contract unless it acted promptly to ensure that its subcontractor, Alstom, was delivering on the agreed safety standards.

He said: “If a safety breach caused by gross incompetence or wilful default leads to a material breach of the contract, then the ultimate sanction is to force the sale of the contract.”

Tube Lines and Metronet’s financial backers were given “letters of comfort” by the Government before the Tube’s part-privatisation in 2002 to protect them from future liabilities. The letters do not protect the companies in the event of persistent safety breaches.

Tube Lines, which manages the Northern, Piccadilly and Jubilee lines, is owned by Amey and Bechtel and made profits of more than £1 million a week last year.

LU’s spokesman said that LU found it “frustrating” to have to go through Tube Lines rather than intervene directly with Alstom. “This is the kind of problem that Transport for London repeatedly warned was likely to happen under the PPP,” he said.

Mr Livingstone failed twice in the High Court to block the PPP on the ground that splitting maintenance from train operation was unsafe. Last year Transport for London took control of LU, which oversees the PPP contracts.

The fault on the Northern Line was first reported on December 9, when a driver was ordered to run through a signal that had jammed on red. The train should have stopped automatically as it passed the light, but this did not happen. The emergency braking device, known as a “trip cock”, failed in tests on three more occasions. The fourth failure, last Wednesday, prompted LU to order Tube Lines to inspect all trains.

The emergency inspections resulted in Tube Lines delivering only just over half the 90 trains needed for a full service on Friday, causing chaos on the Northern Line, used by more than 700,000 passengers a day.

On Friday, LU issued an emergency direction to Tube Lines to give access to LU’s own inspectors, led by David Waboso, engineering director. The team has been inspecting the maintenance regime at Alstom’s two depots in Morden and Golders Green. They found a series of faults, including loose bolts and failure to maintain the mechanism that re-sets the trip cocks.

Terry Morgan, chief executive of Tube Lines, admitted that Alstom’s maintenance had been inadequate. The Northern Line has been the worst- performing Tube line this year and the only one that has failed to meet PPP reliability targets.

Mr Morgan said that bad delays on the Northern Line at the weekend and yesterday were a result of union demands that each train have two drivers until trip cocks were repaired.

He suggested that LU had let itself be bullied by the RMT transport union into overreacting to the problem and leaving itself without enough drivers for a full service.