Underground drivers who belong to the RMT walked out at 12.00, and Transport for London is warning of ‘severe delays’ on several of the lines which still have a service. The Mayor of London is calling for a ‘swift resolution’ to the dispute, which involves the introduction of a four-day working week.

At 12.50 TfL reported that there was no Circle line service, and that Metropolitan line trains were not running between Baker Street and Aldgate, while there were no Piccadilly line trains beyond Acton Town to Heathrow or Uxbridge, although earlier predictions that there would be no service at all on the Piccadilly line have not been justified so far.

Services which do run will finish early, with last trains expected at about 20.00.

This first walkout will continue until midday tomorrow, but TfL said disruption was expected to continue for the rest of the day.

A second 24-hour strike is set to start at midday on Thursday.

In a statement, the Mayor of London Sir Sadiq Khan said: ‘Strikes are bad for London and bad for Londoners, particularly for all those businesses who rely on commuters coming into our city.

‘Most of the Tube and TfL services will continue to run throughout this week, but Londoners should check before they travel.’

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