Nurses, midwives and health workers at the Royal Free and Whittington hospitals have joined colleagues across the NHS in England and Northern Ireland in striking this morning.

Picket lines involving six trade unions will continue until 11am this morning as part of a long-running dispute over pay.

Today’s four hour strike action - the largest for more than 30 years - will be followed by an “overtime ban” in the ambulance service from tomorrow until Friday, with other NHS employees only working to their contracted hours during the same period.

Urgent and emergency care will be unaffected.

It comes after the government ignored judgements made by the independent NHS Pay Review Body saying all NHS staff in England should receive a one per cent pay rise from April 1.

Health secretary Jeremy Hunt said the requested pay increase would lead to job losses.

He told the BBC Radio 4 Today programme: “Nearly 60 per cent of NHS staff get an automatic pay rise through their increments of an average of 3%.

“We can’t afford to offer a 1% on top of the 3%.

“We have had very clear analysis that if we did that, hospital chief executives would lay off around 4,000 nurses this year and around 10,000 nurses next year.

“The NHS has just come through a terrible tragedy with Mid Staffs when we discovered the most appalling care happening there and indeed some other hospitals as well.

“We have turned the corner on that by recruiting in hospital wards around 5,000 extra nurses in the last year alone. We don’t want to turn the clock back on that.”

Several trade unions are involved in the strike action, including those representing nurses, paramedics, hospital porters and ambulance crews as well as the Royal College of Midwives (RCM), who are striking for the first time in its history.

Annie Black, a Camden resident who has been a midwife for 12 years, said: “We haven’t had a pay rise for years yet our workload keeps on increasing.

“It’s time the Government took us seriously. It’s weird being on strike, but we feel that enough is enough.”

The dispute involves over 400,000 NHS staff, who have been hit by pay freezes or below inflation rises since the coalition came to power in 2010.

Unite said a poll it commissioned showed public support for the industrial action as well as backing for a decent pay rise.

Unions are protesting at the Government’s decision not to accept the independent pay review body’s recommendation to award a 1% pay rise to all staff.

Instead, ministers took the “divisive” decision to only award a 1% pay rise for those on the top of their pay band, which unions say has denied it to 60% of NHS workers.

Christina McAnea, national officer of Unison, said: “This is the first time in 32 years that NHS workers take industrial action over pay, and for many, it will be the first time. Up and down the country, hundreds of thousands of workers are out fighting for fair pay and for the NHS.”

TUC general secretary Frances O’Grady, who joined a picket line near Euston in London, added: “NHS staff are always reluctant strikers - there hasn’t been a national strike over pay in the health service since 1982 - and they will do everything they can to protect patients in their care. But morale has hit rock-bottom.

“Not only have NHS staff faced year-on-year cuts in the relative value of their pay, ministers have turned down the recommendations of the independent pay review body, even though it called for an affordable, below-inflation pay rise.

“It is no surprise that the NHS is finding it hard to recruit and retain staff as they find themselves squeezed between falling living standards and covering up for NHS cuts.”

Cathy Warwick, chief executive of the RCM, said: “At a time when MPs are set for a 10% pay hike, we’re told that midwives don’t deserve even a below-inflation 1% rise. And politicians wonder why the public does not afford them more respect.

“It feels to a great many people, including midwives, that there is one rule for them and another rule for everybody else.

“The independent panel of experts who advise the Government on NHS pay recommended a 1% pay rise for midwives, nurses, paramedics and other NHS staff. Unfortunately, Health Secretary Jeremy Hunt rejected that recommendation, and he and the employers decided that midwives and others won’t get a pay rise this year.”

NHS England’s chief nursing officer Jane Cummings said: “We know that NHS staff are highly professional and always wish to put patients first. I am sure they will think very carefully before taking strike action to ensure the safety and care of patients is not put at risk.

“As a nurse, I know that Monday mornings are often extremely busy for the NHS and it may be busier than normal this Monday because of the strike action being taken by some staff. As ever, the safety and care of patients is our top priority and we have robust plans in place to cope.

“If necessary, the most urgent cases will be put first and we would ask the public to help, for example, by only calling an ambulance if it is a life-threatening situation.”