British workers on Eurostar trains that run across the English Channel will strike for seven days in August, including a bank holiday weekend, in a dispute over work-life balance, said the Rail, Maritime and Transport Union (RMT).

55 members of the RMT union will walk out from 00:01 GMT on Friday 12 August until 11:59 GMT on Monday 15 August and for three days over the bank holiday weekend from 23:01 GMT on Saturday 27 August until 22:59 GMT on Monday 29 August.

The Eurostar, which is majority-owned by the French state rail operator SNCF, told AFP that a “maximum of two return trains a day, so four services” will be cancelled each day of the strike.

The strike was announced on the third day of the RMT’s week-long strike on Southern rail services concerning plans to downgrade the role of train conductors, and one day after the union announced a majority of on-board staff at Virgin Trains East Coast had voted to strike.

The union said the strike was called due to a long-running dispute over the Eurostar’s failure to honor a 2008 agreement to provide staff with a better work-life balance in terms of unsocial hours and duty rosters.

“Our train manager members at Eurostar have a heavy commitment to shift work and unsocial hours and are sick and tired of the company’s failure to honor agreements,” said the RMT General Secretary Mick Cash.

“Our members have every right to have a fair work-life balance that fulfils the operational needs of the company while guaranteeing quality time off for friends and family.

“It’s now time for Eurostar to come to the negotiating table with a set of proposals that honours our agreements and guarantees our members a genuine work-life balance.”

RMT Assistant General Secretary Mick Lynch told BBC Radio: “Our members are sick and tired of waiting for this…We don’t want to be on strike, we don’t want our members and the public inconvenienced this way.

“We’re ready to make an agreement today or tomorrow or whenever the company wants to speak to us.”

A Eurostar spokeswoman said: “We will of course be using more of our continental crew,” noting that only British employees are involved in the strike-action, and the company will rely on French and Belgian employees to fill in some of their jobs.

“We are aware of the plans for strike action and our focus has been seeking a joint resolution while planning to provide a good service for our customers,” said the company in a statement.

“On the days of the strike we have made some small changes to our timetable to ensure that all passengers booked to travel will be able to on those days. Passengers affected will be notified in advance.”

Although the company said that they are currently “seeking a joint resolution,” they declined to comment on the details of the ongoing negotiations.

RMT spokesman Geoff Martin said that negotiations concerning train managers work-life balance had been suspended but he expected the strike announcement to “focus minds” and lead management to return to the negotiating table.

He also said that the union expected the industrial action to have a significant effect on Eurostar rail services, saying that agency workers could not easily replace train managers as they have important security responsibilities.