More than half a million British workers are due to take strike action through Wednesday, with unions across a range of sectors in industrial disputes over pay and working conditions.

They include 300,000 teachers in England, who the National Education Union says have experienced at least a 23% real-terms pay cut since 2010; teachers across two unions in Scotland; around 100,000 civil servants across more than 100 departments, including driving instructors, coastguards and Department of Work and Pensions staff; 70,000 university workers, including lecturers and security staff; and roughly 100,000 train drivers.

Such widespread strike action has not taken place since a dispute over public sector pay in 2011, when more than a million workers are estimated to have taken industrial action.

Tens of thousands of schools will be closed or partially closed, travel and other services will be disrupted, while workers will set up hundreds of picket lines and hold rallies.

Demands vary by union but include inflation-beating pay rises, including to redress historic real-terms pay falls; pensions reform; and no cuts in redundancy terms. The NEU says teaching is in “crisis” as staff are driven from the profession and is calling for an above-inflation pay rise.

Protests will also be over a bill that was passed in the lower house of Parliament on Tuesday which seeks to enforce minimum service levels in some sectors, with some workers able to be fired if they refuse to work when required on strike days.

Most unions are holding several days of strikes, some, like rail, spread across months. Wednesday has been co-ordinated by the unions as a day of mass walkouts to send a message.

It follows strikes by National Health Service ambulance drivers and nurses, who are calling not only for a pay rise but say labor shortages have made working conditions near-impossible.

Postal workers have also been on strike, and firefighters have voted for future strike action.

Average pay excluding bonuses rose by 2.7% in the public sector between August and October, as inflation rose above 10%. That compared with a 6.9% pay increase in the private sector, according to national statistics.

While inflation has begun to cool slightly it remains at historic highs, and acute in areas that most impact workers on lower salaries. Grocery price inflation hit a record 16.7% in the four weeks to Jan. 22.

The Trades Union Congress has described the bill as “wrong, unworkable, and almost certainly illegal.”

On Wednesday’s widespread strike action, a government spokesperson told CNBC: “Ever since these strikes were threatened, the government has been preparing to do all it can to mitigate any disruption caused and we have extensive contingency plans in place.”

“Of course, the best mitigation would be for union bosses to call off planned strikes, to keep talking and to come to an agreement,” CNBC reports.