They will join more than 130,000 civil service workers in staging strike action on Friday 28 April in an ongoing dispute with the government over pay, pensions and job security.

It follows action over Christmas and in the lead up to new year, as well as several subsequent walkouts at ports across the UK and in northern France.

The PCS union, which represents around more than 130,000 civil service and public sector workers, said a month of action beginning 3 April "to increase pressure on government" would culminate in the all-out strike on 28 April.

It is understood the union represents in excess of 15,000 Border Force officials. The government drafted in additional civil service and military resource to mitigate the strikes over Christmas and new year, during February half-term and on Budget day (15 March), all of which passed off without significant incident.

“Our members are not backing down in this dispute," said PCS general secretary Mark Serwotka. "Ministers need to take notice that we’re escalating our action and they need to resolve the dispute by putting money on the table. 
"The new strikes and another national day of action will pile the pressure on a government that refuses to listen."