THE MAYOR of London has apologised to commuters for “teething problems” with new Metropolitan line trains.

Tube users in Harrow have been hit with severe delays since the introduction of new air-conditioned trains on the line, with the rollout of the 58 trains set to continue until late 2011.

Bosses were even forced to close parts of the Metropolitan and Jubilee lines during rush hour last month, strengthening the argument the underground network is strained under the dual pressure of cutbacks and ongoing upgrade work.

But Boris Johnson said the upgrades were necessary to cater for increased demand.

He said: “I know that people are experiencing delays and problems, and there will always be teething problems with any new service.

“I want to apologise for the delays people are having to put up with, but I do think we are starting to see some progress.

“We have to improve how we get information to people about problems but I feel we will see a better service in the future. By 2012 we will see vast improvements.”

In January, Anthony Wood, vice chairman of the Federation of Metropolitan Line Users' Committees, told the Harrow Times:“Everything new has teething troubles but we seem to have had a lot of this.

“This is not acceptable to us and we've made our feelings known to management and they are holding various meetings.

“The situation isn't getting any better, it's getting worse.”

London Underground says that when the upgrade is complete the line capacity will increase by 27 per cent, which means the service will be able to carry an extra 9,500 people per hour.