UK rail staff disrupted the New Year return to work on Tuesday in the latest strike action by workers in a range of sectors over the worst cost-of-living crisis in a generation.
Workers across the economy are at loggerheads with the government as they demand big pay rises to cope with decades-high inflation, currently running at nearly 11 percent.
Normally bustling London train stations were quiet on Tuesday, the first normal working day of 2023 after the New Year break.
Network Rail, which operates the UK's rail services, warned travellers of "significantly reduced" train services or no services at all in some areas until Sunday.
Five days of strike action beginning on Tuesday were to include two 48-hour strikes by around 40,000 members of the RMT union.
The Aslef union will also strike on Thursday.
Transport Secretary Mark Harper urged the rail unions to return to the negotiating table.
"The trade unions decided they wanted to go on strike this week, which is deeply unhelpful, damages the rail industry, damages the interests of the people that work in it," he told Sky News.
"I want to see them back around the table and we can try and hammer out a deal between the employers and the trade unions."
The RMT union, however, accused the government of intervening in negotiations in December to stop a deal. Harper denies the claim.
RMT general secretary Mick Lynch said the minister had scuppered a potential settlement by insisting on the removal of guards from trains, in favour of driver-only operated trains.
The issue is a key one for unions.
"So that prevented any move forward on the issue and so that is the direct responsibility of the Secretary of State (Harper)," Lynch said from a picket line at London's Euston Station.
Despite escalating pay demands, Prime Minister Rishi Sunak has pledged to fight calls for inflation-busting rises, insisting the government must stick to more modest increases for public sector workers.
"The best way to help them and help everyone else in the country is for us to get a grip and reduce inflation as quickly as possible," Sunak told a watchdog panel of MPs late last year.
Those striking in 2022 included rail, port, border force and postal workers along with lawyers, nurses and ambulance staff.
More stoppages are planned later this year.