Schools and colleges in England will be asked to make sure a minimum number of staff are working on any future strike dates, the government has announced.

Ms Keegan said it will initially be a voluntary program, but later the government may use powers it introduced earlier this year.

“Undemocratic” and “unworkable” were the words used by the National Association of Head Teachers (NAHT).

In her statement, Ms Keegan refers to the Strikes (Minimum Service Levels) Act, which applies to a variety of workers.

In its statement, the government said the law would guarantee workers’ ability to strike while ensuring the public’s access to essential services.

In the event of future strike action, the Department for Education states that the agreement will protect children, young people and parents.

“This is nothing short of an overtly hostile act by the government and an attack on the basic democratic rights of school leaders and teachers,” said NAHT general secretary Paul Whiteman.

This comes at a time when the government should be building bridges with the profession.”

A pay dispute with the government led to four unions in England striking earlier this year.

During previous strikes, headteachers were planning to support GCSE and A-level students, and unions said they would ensure those students were in class during exam preparation.

There was an offer accepted by the unions in July, but NASUWT members are currently opting not to strike in English schools.

The government will set minimum service levels after consulting with the public under the new law, which will apply to England, Scotland, and Wales.