UK Border Force staff are to strike over the busy festive holidays at airports across the country in a dispute over pay and conditions, a union has announced. Passport checks at Heathrow, Gatwick, Manchester, Glasgow, Cardiff and Birmingham airports will be among those disrupted, the PCS union has said. Days affected will include the period from 23 December to Boxing Day inclusive, and from 28 December to New Year’s Eve. Union members are also expected to strike at Newhaven port in East Sussex and at the Highways Agency on strike dates coordinated with RMT action on the railways, the union said. The strike is expected to affect hundreds of thousands of people planning to go on holiday. The government has been preparing for the strike by training 600 soldiers to check passports instead. The announcement came on the same day Rishi Sunak promised “new tough laws” to curb the impact of industrial action as he criticised “unreasonable” unions. Mark Serwotka, the PCS general secretary, announced the dates after 100,000 PCS members in 214 government departments and other public bodies voted to take action in support of a 10% pay rise, pensions, job security and no cuts to redundancy terms. Serwotka said he had written to Adm Sir Tony Radakin, head of the armed forces, calling for the withdrawal of British forces from covering for striking workers. Soldiers have received between three and five days of training so they can cover for Border Force staff, who usually receive between three and five weeks of training before being assigned a mentor for at least a month. Members of the armed forces could also be brought in to help drive ambulances and fire engines in other disputes, ministers have said. Border Force staff are among many public sector workers who worked in close contact with the public throughout the pandemic. Serwotka urged the government to come forward with a new deal for its members after ministers refused to increase a 2% pay offer. “They keep saying their door is open, but it is a very strange door because there’s nothing behind it. This strike would not happen if Mr Sunak and Mr Hunt paid their staff so they can put food on the table,” he said. “We have no option but to take industrial action because our members are using food banks and not able to switch on the heating right now.” Serwotka also raised the prospect of coordinated action with other unions involved in disputes. “The government can stop these strikes tomorrow if it puts money on the table,” he added. “Like so many workers, our members are struggling with the cost of living crisis. They are desperate. “Some sections of the media have accused us of playing politics with these strikes. Let me be clear: our dispute is with the employer.” Robert Jenrick, the immigration minister, said the decision to strike was “unjustifiable and will ruin the plans of thousands of families and businesses across the country”. “While we are working closely with all UK ports and airports and have robust plans in place to minimise any delays if strike action goes ahead, passengers should be prepared for their plans to be severely disrupted,” he said. “Those intending to travel over strike days should keep up to date with the latest advice from operators before making journeys this Christmas.” Serwotka warned that it was only the “opening shots” of the dispute – suggesting that immigration staff at the Port of Dover could also walk out in the weeks ahead. The PCS represents about 15,000 Home Office staff in total. The union has already revealed strikes at the Department for Work and Pensions (DWP) and among driving examiners in December. A spokesperson for Heathrow, where strikes will affect terminals 2, 3, 4 and 5, said: “The Home Office advises that immigration and customs checks may take longer during peak times on strike days, and Heathrow will support Border Force to minimise these impacts. “Passengers are advised to check their flight status with their airline before travelling.” The airport pointed out that the workers involved in the strikes were employed by the Home Office, not Heathrow. A spokesperson for the Airport Operators Association said: “There may be a bit more queueing but the system should work.” A Home Office spokesperson said: “We are disappointed with the union’s decision to strike and the inconvenience this will cause to the public and businesses. “We are working closely with all UK ports and airports to ensure we have robust plans in place to minimise any delays if strike action goes ahead; however, passengers should be prepared for potential disruption. We will deploy suitable resource to meet critical demand and support the flow of passengers and goods through our border.”