It failed to meet these 'availability' targets on the Northern and Jubilee Lines but did achieve them on the Piccadilly Line.

The firm did meet targets for ambience, facilities and fault rectification service points.

The number of days where there were no delays reported increased.

Tube Lines said it missed the availability targets because of train problems which it is addressing.

Investment in infrastructure rose to �102.6 million - almost double that of the same period last year.