Hundreds of thousands of workers are going on strike, in what will be the biggest day of industrial action for more than a decade.
Teachers in England and Wales who are members of the National Education Union are set to stage walkouts – affecting 23,000 schools.
Estimates from the NEU suggest 85% of schools across both nations will be fully or partially closed today, leaving some parents with no choice but to take leave from work or arrange childcare.
Read more: Who is going on strike and when?
Train drivers from the RMT and Aslef unions are also staging another strike as a long-running dispute over pay and conditions rumbles on – with university lecturers, bus drivers and security guards taking action too.
About 123 government departments are set to be disrupted by industrial action as well.
Protests are due to be held across the country against the government’s controversial plans for a new law on minimum service levels during strikes.
Downing Street has conceded that today’s mass strike action will be “very difficult” for the public.
The prime minister’s official spokesman said it is “disappointing” that headteachers do not know fully how many teachers will be available for work until later today.
Union bosses continue to argue with employers for higher pay rises to combat record high inflation and real-term cuts over the past decade.
The latest research from the TUC suggests that the average public sector worker is more than £200 a month worse off compared with a decade ago.
But ministers continue to insist increasing wages to that level would fuel inflation, and its top priority was to cut that down over the coming weeks and months.
More strikes are expected next week and will be dominated by NHS staff, with both nurses and ambulance workers planning action.
NHS consultants in England are also preparing for possible strike action.
And the following week will see Border Force officers at four ports strike over four days in the February half-term.
Scale of school strikes revealed
Some schools may only open to certain year groups as a result of today’s industrial action.
Liverpool City Council is expecting 38% of schools to be closed, with 54% only partially open, based on returns from 130 of around 160 schools in the city.
Meanwhile, Norfolk County Council said they had already been informed of 121 partial closures and 29 full closures across schools.
The NEU’s joint general secretary, Kevin Courtney, said he and his members “sincerely regret” the impact this will cause to a child’s education and routine, but warned: “We’re pointing to disruption that is happening every day in schools.
“If we don’t persuade government to invest in education that disruption just carries on.”
While a 5% pay rise has been offered to most teachers – covering the current school year – the NEU is demanding a fully funded, above-inflation pay rise.
Today marks the first of seven days of NEU strike action across February and March, but Mr Courtney hopes a deal can be reached before further walkouts take place.
He said: “There are 28 days until the next strike in England. The government can resolve it in that time.”