The silver lining of the signalling black cloud hanging over the Jubilee Line Extension is that the spring 1999 opening will give valuable extra time for contractors to complete their work.
'The key focus is still getting the signalling systems in place, but we have got a lot of work still to do with electrical and mechanical services and getting the escalators finished,' says Doherty.
September 1998, he says, was always a tight date to complete work on the stations, particularly after industrial action by electricians slowed progress. With these problems now resolved he is looking for increased productivity levels to pull these contracts back to programme.
Westminster station still remains the furthest behind. Doherty stresses that even though work will continue in the station until January 1999, it is not critical to the opening of the line. Signalling has taken over in this respect.
Doherty is as usual circumspect about the outturn cost of the project but does admit that February's best guess of £2.76bn could well have reached £2.8bn. He refuses to say how much of the extra cost is down to the signalling problems.
'I think we are at a point now where all the big unknowns are behind us,' he says. 'We will only know the final cost when the bills come in.'
And he maintains that he is not expecting a rash of litigation as contractors sort out their final accounts.
'It is our intention to be right and proper and fair when sorting out accounts. But if someone wants to approach it in a different manner then we are not going to reach agreement. I cannot predict that.'