Train operators will be forced to guarantee that 40% of a normal timetable will run on strike days under a law to be introduced to parliament on Tuesday. The minimum service level regulations would make sure that “certain priority routes can remain open”, the government said, although it was unclear which journeys would be covered. Similar rules will be introduced for Border Force, which will have to ensure staffing levels will be at a level that means they are no less effective than normal. Ambulance workers in England will also be bound by minimum service regulations during strike action, so that they always respond to life-threatening cases or if there is no clinical alternative. Even without strikes, ambulances are not always able to attend all calls. The Conservatives have grappled with a wave of strike action by rail workers, teachers, health workers and others fuelled by anger at the failure of pay to keep pace with soaring inflation. Disputes – some of which have since been resolved – have also centred on deteriorating working conditions, and the strikes have caused major disruption across England and Wales. The government said minimum service levels would ensure that public services continue in the face of strikes, calling the measures “effective and proportionate”. It follows the introduction of the Strikes (Minimum Service Levels) Act this year, which faced fierce criticism from trade unions as unworkable and a threat to the right to strike. Rishi Sunak said the new regulations would prevent unions from “de-railing” Christmas for millions of people, with ministers hopeful that the legislation can be completed before the festive period. “This legislation will ensure more people will be able to travel to see their friends and family and get the emergency care they need,” he added. “We cannot go on relying on short-term fixes – including calling on our armed forces or civil servants – to mitigate the disruption caused by strike action.” Under the legislation, employers would issue work notices to identify people who are reasonably required to work during strikes, with unions compelled to take reasonable steps to make sure members comply or else lose legal protection from damages claims. Paul Nowak, the general secretary of the TUC, said: “The crisis in our public services is of the government’s own making. Rather than engaging constructively with unions, they are attacking the right to strike, and they are punishing paramedics and rail staff for daring to stand up for decent pay and better services. “These new laws are unworkable, undemocratic and almost certainly in breach of international law. The UK already has some of the most restrictive trade union laws in Europe. Now the Tories want to make it even harder for people to win fair pay and conditions.” The rail unions also said the measure was unworkable. Maryam Eslamdoust, general secretary of the TSSA, said: “We have been clear with the government – this legislation is not going to work, nor is it needed. Moreover, it’s undemocratic and a direct attack on the right to strike which is at the heart of British democracy. “Again and again ministers attack railway workers by planning to make cuts in the industry and expect unions to stand aside, rather than standing up for members. This will only serve to inflame industrial tensions.” Unions representing ambulance personnel criticised the laws as “pointless”, unlikely to improve 999 response times on strike days and an attempt to “scapegoat” staff for the dire state of the NHS. “Sacking ambulance workers on strike won’t get the millions awaiting hospital treatment any closer to the top of the list”, said Sara Gorton, head of health at Unison. “It’s just a desperate attempt to deflect attention from the government’s appalling record on the NHS.”