The first regulations aimed at ensuring minimum levels of service during strikes have come into force, the Government announced on Friday.

Ministers said the regulations are set to apply in the rail sector, border security and ambulance services.

For the railways, minimum service levels will mean that rail operators can aim to run 40% of their normal timetable during any strike.

For a strike affecting infrastructure services, certain key routes will also be able to stay open and for longer than is normally the case during strikes, said the Government.

A Statutory Code of Practice has also come into force which sets out the “reasonable” steps trade unions should take to ensure their members comply with work notices.

Where minimum service level regulations are in place and strike action is called, employers can issue work notices to identify people who are “reasonably required to work” to ensure minimum service levels are met.

The law requires unions to ensure their members who are identified with a work notice comply, and if they fail to do this, they will lose legal protection from damages claims.

The Government has raised the maximum damages that courts can award against a union for unlawful strike action. For the biggest unions, the maximum award has risen from £250,000 to £1 million.

Rail minister Huw Merriman said: “Strikes cause stress and disruption to passengers and businesses and, whilst there is no silver bullet to mitigating the disruption from strikes, these regulations deliver a manifesto promise and will enable employers to reduce the impact from strikes.

“As the Government, we have a duty to ensure the public can access key services, and while it is important workers maintain their ability to strike, this must not come at the cost of people getting to work, accessing healthcare or education.”

The announcement was made ahead of a special TUC conference on Saturday to discuss union opposition to the new regulations, which they say are unworkable and illegal.

Labour has pledged to repeal the new law if it wins the next general election.

TUC general secretary Paul Nowak said: “The fight against this draconian legislation doesn’t stop here – unions won’t rest until these laws are repealed.

“That’s why we are calling this weekend’s once in a generation special Congress.

“Unions will be discussing how we take on these spiteful new laws and how we step up resistance and campaigning.

“These new Conservative anti-strike laws are unworkable, undemocratic and likely in breach of international law.

“They represent an unprecedented attack on the right to strike – and they’ll poison industrial relations and drag out disputes.”