Eurostar rail workers from two unions are to take part in two concurrent periods of strike action this month in a dispute over their work-life balance.
RMT members will walk out from 12 to 15 and 27 to 29 August while TSSA members will strike on 14 and 15 and 28 and 29.
Transport Secretary Chris Grayling said he was “very disappointed the unions keep calling strike action over what appear to be pretty minor matters”.
Eurostar said all passengers with reservations will be able to travel.
A spokesman said: “On the days of the strike we have made some small modifications to our timetable to ensure that all passengers booked to travel will be able to travel on those days.
“Customers affected by any changes will be notified in advance with options for their journey.”
The company added it has been planning for possible strike action and is still in discussions with the RMT over the dispute, which the union says is over unsocial hours and duty rosters for about 80 train managers.
‘Quality time off’
Eurostar runs services between London and mainland Europe and the walkout coincides with the Assumption Day bank holiday in France and Belgium on 15 August and the 29 August bank holiday in England, Wales and Northern Ireland.
The RMT says Eurostar has failed to honour an agreement from 2008 over conditions for their staff.