The operator of the Caledonian Sleeper has announced it will cancel all services during an 11-day strike by rail workers later this month.
The move by Serco comes after the RMT union confirmed strike action would take place between 15 and 26 June following a ballot of members.
The RMT claims that Serco attempted to "impose a pay freeze" on rail staff.
However, the rail operator described the proposed action as "both unjustified and very disappointing".
It said it would cause "significant disruption" for people who had booked to travel on board the overnight rail service between London and Scotland.
'Open to discussions'
Caledonian Sleeper managing director Kathryn Darbandi said all staff had received full pay throughout the pandemic, despite a "significant" reduction in services.
She said: "We have also been clear that we fully intend to resume pay talks next year, once the business is in a stronger position.
"We remain open to discussions aimed at resolving the dispute, but in the meantime, we have had no choice but to prepare for the strike to go ahead."
She added: "We're sorry that guests will be affected by this strike action and are contacting them to arrange a full refund."
All staff grades were involved in the RMT ballot, which returned an 85% vote in favour of a strike.
Members have also been instructed not to work any overtime or work on their rest days from 26 June.
RMT general secretary Mick Lynch said: "The company needs to get round the table for real so that we can negotiate a fair pay deal for our members who have kept the service running throughout the pandemic.
"This contempt towards a loyal and dedicated workforce is completely unacceptable and RMT will be backing them all the way.
"The union remains available for talks aimed at resolving this dispute."