Mayor to mount new challenge on PPP

Ken Livingstone is to return to the High Court in a fresh challenge to the Government's partprivatisation of the Tube. The Evening Standard has learned that he will relaunch his legal battle on the basis of "new evidence".

An attempt to stop the publicprivate partnership (PPP) last year failed in the High Court. The fresh case being prepared by Transport for London will say that London Underground's contracts-with the private sector have changed sufficiently to justify a new challenge.

This will put pressure on new Transport Secretary Alistair Darling, who is already facing the prospect of strikes in protest over the claimed deterioration of safety under PPP.

It will also dismay Downing Street, which wants the first contractssigned by the end of the month. The signatory is expected to be the Tube Lines consortia which will take over the Jubilee, Northern and Piccadilly lines.

The group consists of Amey, Bechtel and Jarvis, the company responsible for the track involved in the Potters Bar rail crash.

? London Underground today closed four more escalators, this time at Bank station, one of the busiest on the system - for safety reasons.