The first of a series of 24-hour strikes by London Underground drivers ended at noon on Wednesday, but further walkouts are planned in the coming months.
The strike by members of the Rail, Maritime and Transport union (RMT) crippled services again on Wednesday morning, causing travel disruption for commuters and visitors.
Another 24-hour strike will start at 12 noon on Thursday, disrupting services for the rest of the week.
Transport for London (TfL) continued to urge passengers to check before they travel.
The union, which is in dispute over changes to the working week, is planning four more 24-hour strikes in May and June unless the row is resolved.
Pubs and restaurants in London fear that this week’s strikes will have a big impact on their business.
RMT official Jared Wood said union members felt strongly about the issues at the heart of the dispute.
He told the Press Association the row was not just about a four-day week, saying other issues were involved such as the length of shifts and changes to annual leave.
He said: “TfL need to come forward with changes to their proposals for this dispute to be resolved.
“There is absolute unanimity among our members that we have to fight these proposals.”