Home secretary Suella Braverman has warned Britons to “think carefully” before going ahead with plans to travel abroad this Christmas.
Ms Braverman said planned strikes by Border Force officials will “undeniably” cause serious disruption to hundreds of thousands of travellers hoping to use ports and airports.
The home secretary confirmed she has plans to call in the military to fill the places of striking workers.
But she said she would not compromise on security at the border to ease the expected queues and delays, and told would-be travellers to expect long waits.
The PCS union on Wednesday announced eight days of industrial action which will see Border Force personnel down tools from 23-26 December and again from 28-31 December.
Staff manning passport booths will take action at Heathrow, Gatwick, Manchester, Birmingham, Cardiff and Glasgow airports and the port of Newhaven in a dispute over demands for a 10 per cent pay rise and job security.
Ms Braverman told the BBC: “It is very regrettable that they have made this decision to potentially strike over critical times in the run-up and following Christmas and the New Year.
“If they go ahead with those strikes, there will be undeniable serious disruption caused to many thousands of people who have holiday plans.
“I really want to urge people who have got plans to travel abroad to think carefully about their plans because they may well be impacted.”
PCS general secretary Mark Serwotka yesterday wrote to the head of the armed forces Admiral Sir Tony Radakin, warning him that it would be “outrageous” for troops to be deployed as strike breakers during the dispute.
And there are reports that soldiers are unhappy at the prospect of being told to give up their Christmas to fill in for workers who in many cases are earning more than them.
One unnamed senior military source told the Daily Telegraph: “The government’s first lever it reaches for every time there is any difficulty – whether it’s floods, strikes, all the rest of it – is the Armed Forces, as opposed to it being the last resort.”
But Ms Braverman said: “We’ve got plans in place that will involve to a degree bringing in some of our military colleagues to help us in a variety of roles.
“Ultimately, I’m not willing to compromise on security at the border. That’s the number one priority.
“So that may well have another an adverse impact on convenience for people, frankly, whether it’s the time that they may have to wait for flights. They may well be delayed on arrivals and various travel plans.
“Ultimately, security at the border is my number one non-negotiable priority.”