The admission by London Midland came as Northampton's MPs prepare to discuss the problems with the rail service with the Transport Secretary on behalf of beleaguered travellers.

Since a new timetable was introduced three-and-a-half weeks ago, commuters have faced increased fares, cancellations, the loss of the high-speed 7.12am service and four high-profile incidents in the six days.

Northampton's MPs will meet Transport Secretary Geoff Hoon to discuss the services.

Brian Binley, the Conservative MP for Northampton South, said: "For a growth area, specially designated by the Government, to be suffering this disastrous performance by both Network Rail and London Midland is totally unacceptable.

"Somebody has got to get their act together and I will say no to every major planning proposal until such time as we have a proper infrastructure in place, which includes proper rail services which will serve the people of Northamptonshire both now and in the future."

Sally Keeble, the Labour MP for Northampton North, said a recent survey conducted by Northampton Rail Users' Group showed a good transport service was a key part of people moving to live in the town.

She added that, although her meeting with Mr Binley and Mr Hoon was originally to discuss the new timetable and cancellation of the 7.12am, it had been overtaken by recent events.

Mrs Keeble said: "If they want Northampton to grow, we have got to have the service. What's happening now is completely inadequate.

"There has got to be some kind of assurance about the quality of the service."

A London Midland spokesman said: "We are working hard to improve our performance.

"We accept we have had a number of services affected by delays or cancellations in the first weeks of our new timetable and we accept that our performance has, in cases, been poor and we are working on ways to improve it."

He said the company had recently invested £190 million in Northampton, for a new depot and 10 new trains.