Public sector strikes begin toady as 750,000 workers walk out of their jobs in protest over changes to pensions.
Schools, airports, jobcentres, courts, libraries, museums and tax offices will be disrupted by the strikes today.
However schools will be the most affected, with up to 85% closing today.
The strikes have been slammed by Prime Minister David Cameron and Labour leader Ed Miliband.
Cabinet Office minister Francis Maude, who is leading talks with the striking unions, called on Britain to find its “Dunkirk spirit”.
“I urge public sector workers to go to work today,” Maude said.
How you will be affected by the strikes today
Schools, Colleges and Universities
The NUT expects around 17,000 schools in England (85%) to be closed.
350 universities and 75 colleges will close, according to one of the unions involved.
Ports and airports
Travellers have been warned to expect long delays at passport control as they arrive at ports and airports.
Up to 9,800 immigration and customs workers, who are PCS union members, could walk out.
People who claim benefits do not have to sign on as usual today. Some job centres will be closed.
Driving tests will be cancelled as a number of local DVLA offices will not open.
A number of non-urgent trial ill be postponed although the Ministry of Justice said it could not confirm how many courts will be affected.
Some staff at coastguard search and rescue centres will strike but helicopters and lifeboats will operate as normal.
Which unions are on strike?
Public and Commercial Services Union (PCS)
National Union of Teachers (NUT)
Association of Teachers and Lecturers (ATL)
National Association of Head Teachers (NAHT)
University and College Union (UCU)
First Division Association (FDA)
Trades Union Congress (TUC)