Tube drivers are to stage a series of 24-hour strikes in the next few months in a dispute over a four-day week, the RMT union announced on Friday.

The walkouts on the London Underground will take place on eight separate days between Thursday, November 26 and Thursday, February 25.

The shock news was immediately slammed by business chiefs in London and the Aslef train drivers’ union which has hailed the reforms as offering Tube drivers the best working conditions on the rail network.

The RMT and Transport for London have been in talks for months over a four-day week for Tube drivers, many of who earn on average more than £70,000, after industrial action earlier this year.

TfL presented the union with the final proposals a few weeks ago and they have failed to break the deadlock in the negotiations over the changes which have been fully backed by the Aslef union.

The 24-hour strikes will begin at noon on the following dates:

RMT general secretary Eddie Dempsey said: “London Underground is attempting to dress up a wholesale attack on drivers' working conditions as a voluntary four-day week.

“But there is nothing voluntary about a scheme that forces drivers to give up existing protections whether they work four days or five, and threatens those who refuse with displacement from their depots.”

But London Underground rejected his claims.

LU director of customer operations Nick Dent said: “We have engaged with our trade unions for months about our proposal for a new four-day working week.

“As a result of that engagement, drivers can now choose to remain on a five-day week with a guarantee of remaining at the same depot.”

The industrial action, which threatens to cause travel chaos ahead of Christmas and into the New Year, was condemned by business chiefs.

Karim Fatehi, chief executive of the London Chamber of Commerce and Industry, said: “The days immediately before Christmas are vital trading days for thousands of businesses across the capital, while hundreds of thousands of visitors come to London over the festive period to shop, dine, stay in hotels and enjoy everything the city has to offer.

“Disrupting the transport network at this time risks costing businesses valuable revenue, deterring visitors and making it harder for staff and customers to get around.“

Allen Simpson, Chief Executive of UKHospitality, said: “Tube strikes have a devastating impact on London’s hospitality businesses, with fewer people travelling into the capital, lost sales and staff struggling to get to work.

“The timing of these strikes will be particularly damaging, with two falling in the crucial trading period just before Christmas. The sector is already operating under enormous cost and tax pressures, and disruption at one of the most important times of the year will only add to the challenges they face.

“We urge all parties to find a resolution and avoid action that would put yet more pressure on hospitality businesses and workers across London.”

Shadow Transport Secretary Richard Holden added: “These RMT militants who bankroll hand-picked Labour MPs do not care about better services, they do not care about passengers and they do not care about our capital city – all they care about is beating as much cash out of this weak piñata of a Labour Mayor and Government as they can.”

Finn Brennan, Aslef’s full-time organiser on London Underground, voiced “surprise” that the RMT was striking “to try to prevent Underground drivers moving to a four-day week on a voluntary basis”.

He added: “The voluntary four-day week gives Tube train drivers an extra 35 days off every year with rosters based on a 34-hour week in return for some changes to working conditions and moving to electronic, rather than paper-based, systems for booking on for duty.

“A strike designed to stop people having the choice of a shorter working week and more time off is a strange choice to make.”