Up to 1 million expected on streets in mass industrial action protesting at pay freeze and pensions as result of austerity cuts

Britain is to witness the biggest round of industrial action for three years as teachers and firefighters join care workers, refuse collectors, librarians and other civil servants at picket lines and rallies across the country.

Up to a million people are expected to take part in the protest on Thursday, as workers protest about the public sector pay freeze, falling living standards and pensions.

Dave Prentis, general secretary of Unison, representing many of the country's lowest paid workers, told the BBC: "Something has got to give – enough is enough.

"We've got 300,000 now on zero-hours contracts, we've got a million workers in local government earning below the living wage that Boris Johnson and others talk about, and people are saying: 'We cannot go through another three years of this pay restraint.'"

Union leaders say there will be more than 50 marches and rallies across England and Wales including a protest that will end in a rally at Trafalgar Square, London. There will also be scores of picket lines at schools, council offices, depots and fire stations across England and Wales.

Public sector workers and members of the GMB union make their way through Brighton, as they take part in the one-day walkout. Photograph: Gareth Fuller/PA

The TUC's general secretary, Frances O'Grady, who is joining picket lines in London on Thursday morning, said public sector staff were being "locked out of the recovery". She added: "Across the public sector workers are on strike today to say enough is enough. Year after year, pay has failed to keep up with the cost of living. Public sector workers are on average more than £2,000 worse off under this government."

The government implemented a public sector pay freeze for two years from 2010–12 and has subsequently imposed a 1% pay cap, meaning some of the lowest paid workers have seen their income fall in real terms for more than four years.

O'Grady said: "Nearly half a million local government workers earn less than the living wage. But even as the economy starts to grow, ministers have told them that the pay cap will last until at least 2018.

"This is why today's strikers deserve public support. They are saying that ordinary workers should not be locked out of the recovery, and that we should all get a fair share as the economy grows again."

However, Francis Maude, the Cabinet Office minister, argued that keeping down public sector pay was necessary to pay down the UK's debts. He told BBC Radio 4's Today programme that more public sector jobs and frontline services would have had to be cut without wage restraint.

"We can't just carry on mounting up debts year after year after year that our children and our grandchildren are going to have to pay off, so we needed to have pay restraint and we've tried to protect the lowest-paid public sector workers by ensuring that they weren't subjected to the pay freeze," he said.

A Cabinet Office spokesman said: "The vast majority of dedicated public sector workers did not vote for today's action, and early indications are that most are turning up for work as usual. We have rigorous contingency plans in place, services appear to be working well and we expect most schools and jobcentres to open their doors.

"In the civil service we estimate that fewer than 90,000 members of the PCS union will not be working – this is lower than previous strike action, and just a fifth of the civil service workforce. It is disappointing that, once again, some union leaders have pushed for strike action that will achieve nothing and benefit no one.

"Union leaders have relied on mandates for action that lack authority – the National Union of Teachers ballot was run nearly two years ago, while other ballots had extremely low turnouts."

On Wednesday, the TUC published research showing that since the coalition took office, local government workers, NHS staff, teachers, firefighters, civil servants and other public servants were on average £2,245 worse off in real terms.

O'Grady said: "It won't have been an easy decision for hard-pressed public sector workers to vote to lose a day's pay this week, nor will they take delight in any disruption caused to the public. But if the government continues to hold down pay, our public services will struggle to hold on to and recruit skilled and dedicated staff. When that happens, we all pay the price."

Mark Serwotka, the general secretary of the Public and Commercial Services Union, which represents civil servants and is joining Thursday's strike, said: "Wages are falling further behind the cost of living and in the last four years some civil servants have seen their income fall by 20%. Unequal pay is also rife, with some paid thousands of pounds less than their colleagues doing similar work, and women paid up to 14% less than men."

He said the "meagre economic recovery" was only benefiting the better off. "We need an alternative to cuts where we invest in public services to help our economy to grow, where jobs are created, not cut, and where we clamp down on the corporate tax dodgers who deprive our economy of tens of billions of pounds a year."

The National Union of Teachers is also taking part in the industrial action. Christine Blower, the NUT general secretary, said her members "deeply regretted" going on strike, but that they had little option after months of talks aimed at addressing growing concerns over pay, pensions and conditions of service had failed.

"Teacher morale is at a low ebb. Thousands of good, experienced teachers are leaving or considering leaving their job and a teacher shortage crisis is looming. Ofsted itself says that two in five teachers are leaving the profession in their first five years. This is a very serious state of affairs and is a direct result of this government's policies."

She added: "The fact that teachers are prepared to take strike action is an indication of the strength of feeling and anger about the government's imposed changes. The profession is on its knees. Strike action is a last resort but, due to the intransigence of the coalition government, it is one which we cannot avoid. Unless our concerns are addressed, education will suffer, teacher shortages will worsen and morale in schools will drop even further. [Education secretary] Michael Gove can avoid further disruption by engaging in serious negotiations and making changes to policy."

Striking workers stand outside the National Gallery in central London Photograph: Toby Melville/Reuters

Firefighters will join the action, going on strike between 10am and 7pm. Matt Wrack, the Fire Brigades Union general secretary, said: "The fact that this government has united so many workers to take strike action against them is a testament to the failure of their policies. They are destroying our public services and wrecking the lives of millions. If they won't listen and won't negotiate then this is the result – and they should face more of the same if necessary."

A government spokesperson raised doubts over how many people would be taking part in the strike. A Cabinet Office spokesperson said: "In past years, unions made inflated claims about how many they thought would participate in strike action. They were shown to be wrong. We have rigorous contingency plans in place but we expect the majority of hard-working public servants to turn up for work across the country."