Up to half a million British teachers, civil servants, train drivers and university lecturers walked out over pay and conditions on Wednesday in the largest coordinated strike action in Britain in a generation, causing widespread disruption.

The mass walkouts across the country shut schools, halted most rail services, and the military was put on standby to help with border checks.

About 300,000 teachers are expected to strike on Wednesday, the biggest group involved, as part of wider action by 500,000 people, the highest number for at least a decade.

Mary Bousted, General Secretary of National Education Union, told Reuters that teachers in her union felt they had no choice but to strike as declining pay meant high numbers were leaving the profession, making it harder for those that remain.

"There has been over the last 12 years a really catastrophic long term decline in their pay," she said outside a school in south London.

"None of the people behind me want to be on strike today but they are saying, very reluctantly, that enough is enough and that things have to change."

With inflation running at more than 10% - the highest level in four decades - Britain has seen a wave of strikes in recent months across different sectors, including health and transport workers, Amazon warehouse employees and Royal Mail postal staff.

Education minister Gillian Keegan stuck to the government's position on Wednesday. It has taken a hard line with public sector workers, telling them that giving in to demands for large wage increases will only fuel inflation.

"What we cannot do is give inflation busting pay rises to one part of the workforce and make inflation worse for everybody. That's not an economically sensible thing to do," she told the BBC.

So far the economy has not taken a major hit from the industrial action with the cost of the strikes in the eight months to January estimated by consultancy firm the Centre for Economics and Business Research (CEBR) at about 1.7 billion pounds ($2.09 billion), or about 0.1% of expected GDP.

It put the estimated impact of the teachers' strikes at about 20 million pounds a day.

But the strikes may be having a political impact on Prime Minister Rishi Sunak's government.

His Conservative Party trail the opposition Labour Party by some 25 percentage points in polls and surveys indicate the public think the government have handled the strikes badly.

MORE ACTION

Also on strike on Wednesday are 100,000 civil servants from more than 120 government departments, and tens of thousands of university lecturers and rail workers.

There are also rallies planned for later in the day to protest against a new law to curb strikes in some sectors.

Next week, nurses, ambulance staff, paramedics, emergency call handlers and other healthcare workers are set to stage more walkouts, while firefighters this week also backed a nationwide strike.

Those striking are demanding above-inflation pay rises to cover rocketing food and energy bills that they say has left them stressed, feeling undervalued and struggling to make ends meet.

Outside Bishop Thomas Grant School in Streatham, south London, Natasha De Stefano-Honey, a teacher for the last 14 years, said it was the worst period for education she could remember.

"Maybe 10 years ago I would really recommend teaching as a career and now I am one of those teachers that can't recommend it," she said.

"Although I love teaching it is just so hard, it is just so tiring. There aren't enough of us doing all of the work that needs to be done."