PART of a London Underground line was closed for a while last night after fragments of masonry blocked the track. The debris fell on the Central Line just outside Shepherd's Bush station, and the service was then suspended between Marble Arch and White City.

The debris, from a building site above, was later described as 'loose concrete'.

Transport for London apologised for the delays caused to home-bound commuters, which it attributed to 'emergency engineering work'. Services restarted at about 21.30 after safety checks had been carried out in the affected area.

The debris had come from a building site over the line, where contractors are working on an extension to the Westfield shopping centre. TfL said it was possible to see into the tunnel through a hole. No one was hurt during the incident, and an investigation is under way.