London's transport commissioner has issued a public warning to the private companies running the capital's tube network.

Interviewed in the Independent, Bob Kiley says: "After just one year I am not getting hysterical about it - when plant has been allowed to go to seed you can't get it back in a flash. It's going to be a long, hard slog.

"You have to put in resources over a long period of time, but I'm beginning to worry. They need to step up the pace."