Thousands of members of the Rail, Maritime and Transport union (RMT) are taking industrial action all week in a dispute over pay and hours.
London Underground said there were “minimal” Tube services on Monday, with only a few trains on selected shuttle services.
Buses were busier than usual and more passengers travelled on the Elizabeth Line and London Overground, which were not directly involved in the strike.
There was also a huge increase in the number of people hiring bicycles to get around London.
The RMT has rejected a 3.4% pay rise and is campaigning for a cut in the 35-hour working week, which London Underground says is unaffordable.
Downing Street has called on the RMT and Transport for London (TfL) to get back to the negotiating table to end the strike.
The Prime Minister’s official spokesman said: “I think Londoners will rightly be fed-up with the disruption from Tube strikes ….. as parents try and drop their kids off at school, get to hospital appointments, get to work.
“We want to see RMT and TfL get back around the table when it comes to these strikes, work together in good faith to resolve this situation in the interests of passengers.”
