A massive Tube strike that could deliver a £230m blow to London’s economy was backed by just over half of union members, it can be revealed.

RMT members are preparing to walk out from Sunday – and Transport for London has warned commuters to expect “little to no service” on the Underground between Monday and Thursday next week and, overall, six consecutive days of chaos.

The strike, which threatens transport misery for three million daily Tube passengers, was called by the RMT executive after just over 6,000 members gave their backing – despite almost 4,200 deciding to “sit on their hands” and not take part in the ballot.

Union members voted to take action – before hearing from TfL about the 3.4 per cent pay rise that has been proposed.

TfL has called on RMT chiefs to give Tube staff an opportunity to vote on whether they accept the pay rise.

Research by the central London-based Centre for Economics and Business Research, carried out for The Standard, estimates the strikes will cause a direct £230m hit to the capital’s economy – and countless millions more in indirect impacts

Business leaders have warned the strike will have a dire impact on the capital’s struggling economy. TfL bosses have pleaded with the RMT to back down.

While many commuters will be able to work from home, and the Elizabeth line and London Overground will continue to operate, central London retailers, bars and restaurants all face a noticeable fall in customers.

The CEBR said: “Our analysis suggests that next week’s Tube and DLR strikes could impose a direct economic cost of around £230 million, reflecting the loss of roughly 700,000 working days across both TfL staff and the wider commuter base.

“These figures only capture the immediate disruption, but the true economic hit is likely to be significantly higher once the indirect effects are considered.

“Experience from previous strikes shows that London businesses face reduced productivity as staff struggle to get into the office or arrive late, while shops, restaurants and leisure venues typically suffer from weaker footfall and lower consumer spending.

“On top of that, congestion on London’s roads is expected to increase sharply as people switch from the Underground to cars, taxis and buses, further adding to delays and lost output.

“Taken together, these knock-on effects suggest the strike will have a significant impact on London’s economy for the week and will be felt by sectors ranging from professional services to retail and hospitality.”