A gas leak led to hundreds of people being evacuated from a central London hotel and the closure of two major railway stations during morning rush hour.
A nightclub was cleared and guests at a nearby hotel moved into emergency accommodation after the alert was raised in the early hours. Some 1,450 were moved out of the affected areas.
The capital’s ageing gas pipe network is being replaced. A fire official said there had been a number of recent leaks.
The leak was detected by the Strand in central London, close to the city’s government district at Whitehall, major tourist draws such as Trafalgar Square and the West End theatre district.
Trains were diverted and officials said it could take hours to check buildings to allow people back in.
"Our priority is to get the train stations opened as soon as possible, followed by the buildings,” said gas supplier Cadent.