Trade unions have vowed to oppose any new anti-strike laws tabled by the government, as the home secretary, Suella Braverman, urged the public to reconsider their Christmas travel plans amid “serious disruption” expected to be caused by planned industrial action by Border Force staff. The government is engaged in a bitter PR battle with the unions over who is to blame for the looming wave of public sector strikes. With nurses and ambulance workers due to walk out before Christmas, the cabinet minister Gillian Keegan suggested the government could legislate to prevent workers in health and “critical infrastructure” from taking industrial action. Asked if she backed banning strikes in certain sectors, Keegan said: “Well, yes. We do have some areas where strikes are not allowed as part of the contracts, so for example the military can’t go on strike and the police – there’s some people, as a matter of public safety, you can’t go on strike. “I think what we’re looking at is: are there other areas that we should include in that? Health would be one to look at, and other areas of critical infrastructure.” Any such legislation would almost certainly be too late to avert the currently planned strikes, which include two days of stoppages by nurses, on 15 and 20 December. Steve Barclay, the health secretary, held talks with officials on Thursday over preparations for the planned strike by ambulance staff later this month. His department is also discussing how military personnel could step in, although there has not yet been a formal move to prepare them for deployment. Braverman conceded that walkouts by Border Force over the festive period, which will form part of a series of rolling strikes by members of the Public and Commercial Services union, could result in “undeniable, serious disruption” to “many thousands of people” if they go ahead. In an interview with broadcasters on Thursday, Braverman said: “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.” The government has been preparing for the strike by training 600 soldiers to check passports. Tobias Ellwood, the Conservative chair of the defence select committee, questioned whether soldiers would be able to learn the necessary skills to cover striking workers this winter. Amid growing concerns among defence sources that the armed forces are being asked to cover for Border Force staff and NHS workers, Ellwood said the Ministry of Defence could be forced to call up reserves and that he planned to raise the matter in parliament. “The scale of these strikes are unheard of. This is going to put huge burdens on our military and its questionable whether they can learn the skills sets in time,” he said. “Our forces are adaptable and agile but we are placing quite burden on them. You cannot just drive an ambulance, you have to learn how to use medical equipment. We cannot expect those who are standing in at short notice can meet to the same standard in a short space of time.” With the latest wave of walkouts kicking off with fresh rail strikes next week, Labour accused the government of “grandstanding” over industrial action instead of negotiating with the unions involved. Rachel Reeves, the shadow chancellor, said: “We don’t support new legislation to make it harder to take industrial action; that stops people from withdrawing their labour. What we would be doing in government is not messing around with those laws but getting round the table and resolving these disputes.” But Reeves and Starmer refused to promise at this stage to reverse all of the government’s plans if they become law. The Liberal Democrats’ Treasury spokesperson, Sarah Olney, said: “The government knows that plans to restrict the right to strike would be completely unworkable. These plans are simply a tactic to try and distract from their failure to stop the strikes. “The best way to avoid disruption is to prevent these strikes happening in the first place by getting round the table and working with staff and employers to find a solution.” Unions reacted with fury to Keegan’s suggestion that strikes in key sectors such as health could be banned, with the TUC suggesting such a move could be illegal. “The Human Rights Act protects International Labour Organization (ILO) fundamental convention commitments on the right to strike,” said the TUC’s assistant general secretary, Kate Bell, adding that similar commitments were included in the government’s post-Brexit trade deal with the EU. Gary Smith, the general secretary of the GMB union, whose members are involved in coordinated ambulance service strikes on 21 December, said: “By attacking the right of NHS and ambulance staff to defend their standards of living, this government is showing just how out of touch they are. The public knows who is to blame for the crisis in our NHS – it’s this discredited government.” Christina McAnea, the general secretary of Unison, said: “This threatens to backfire spectacularly on the government. The public has immense sympathy for ambulance workers and their NHS colleagues. Ministers could do well to remember that union members are voters too.”