Katharine Da Costa
BBC health correspondent in Coventry

The ambulance strike here in Coventry started at 06:00 GMT and will end at 18:00 GMT.

About 30 members of the Unite union are out on the picket line this morning with their banners and flags.

Several ambulances with blue lights flashing have already set off on emergencies this morning.

Unions have agreed to cover life-threatening call outs, but lower category callers will be told they’ll have to make their own way to hospital.

The workers here say they don’t want to be striking, but they feel it’s the only way they can put pressure on the government to get fair pay.

Michelle Roberts
Health editor, BBC News online

Some ambulance staff were part of a strike in 2014, but Britain’s last nationwide strike involving paramedics took place in the winter of late 1989 and early 1990.

That strike was also over pay and lasted months, from September through to February.

It began as a ban on overtime work, but later affected non-life threatening calls.

The army, police and volunteer drivers were called upon to help respond to emergencies.

Military personnel have been drafted in to help today in England, but not in Wales, where strikes are also taking place. There are no strikes in Scotland or Northern Ireland.

Image source, PA Media

Michelle Roberts
Health editor, BBC News online

The dispute is largely about fair pay.

The government says the NHS pay award - an average rise of 4.75%, with a guaranteed minimum of £1,400 - meets the requirements of the recommendations from the independent NHS Pay Review Body.

With inflation running at more than 10% and many NHS staff saying they are struggling with the rising cost of living, unions have said this pay award represents an unaffordable real-terms pay cut.

Nick Eardley
Chief political correspondent

There is a blame game playing out about who is responsible for today’s strikes and the disruption they will cause.

The health secretary, writing in the Telegraph, has accused unions of making a conscious choice to inflict harm on patients.

That’s insulting, say unions. One of those involved, Unite, has said any deaths as a result of today’s strikes will “absolutely” be the government’s fault because it has refused to discuss pay.

There were talks between the sides yesterday but because pay wasn’t on the table, unions say the discussions didn’t achieve much at all.

The government is adamant this isn’t an ideological battle - instead it’s about what’s affordable.

But unions are confident they have the public’s backing and are preparing to escalate their action in the new year.

The chief executive of the NHS Confederation - which represents the leaders of NHS services - is appealing to both the government and unions "to leave no stone unturned in trying to find a way of avoiding" further strike action.

Today's strike "could not be happening at a worse time because of the pressures the NHS faces", says Matthew Taylor, speaking on BBC Breakfast, echoing similar comments earlier from the president of the Royal College of Emergency Medicine.

Taylor says: "It is a very tough winter and that's why we need both sides to step away from the rhetoric, and step forward to the negotiating table.

"It is right when the trade unions say even if there was no industrial action, no strikes, we'd still have a workforce crisis in the NHS, we'd still be taking twice as long as we want to take to respond to those category two calls," he says. "This is the situation we're in."

Image source, Getty Images

NHS England medical director Prof Stephen Powis has advised the public: "Don't get so drunk that you end up with an unnecessary visit to A&E".

Speaking on BBC Radio 4's Today programme, he asked the public to be sensible during the season of parties before Christmas, and said that "today is not the best of days to end up in an A&E department if you don't need to be there".

"If you've got yourself blind drunk that doesn't sound like fun to me," he says.

He says emergency services for life threatening conditions will be maintained, including for strokes and heart attacks, and that the NHS has been working very closely with unions to ensure patient safety.

There will be more clinicians than usual in call centres to ensure the right response to patient problems, he says.

He says the advice for the public is dial 999 if you have a life threatening condition, and for non-life threating conditions you should dial 111 for advice.

Unite general secretary Sharon Graham says the trade union has done everything it can to minimise the impact of the strike on patients - and that some workers could come off picket lines if necessary.

"We don't want patients to suffer," she tells BBC Radio 4's Today programme.

She says category one incidents - life threatening conditions - will be responded to immediately, and physicians will triage category two incidents, such as strokes and heart attacks, in case they're also deemed to be life-threatening.

She said blame for the strike "lies squarely at the floor of the government... I've never seen such an abdication of leadership like it in 25 years of negotiating."

Earlier, Health Secretary Steve Barclay said that unions were making a conscious choice to inflict harm on patients.

Image source, PA Media

Around 750 armed forces staff are being drafted in to cover the walkouts in England and Wales.

However, their role will be limited. They won't be sent on call-outs involving critical care and they won't provide any clinical care - but ambulance trainers have told them they should be prepared to hand equipment to their clinical partner if asked.

They also won’t be allowed to go through red lights or turn on blue lights when driving.

Today's strike action by ambulance workers in England and Wales has "come at the worst possible time" as the NHS is already "under immense pressure", says Dr Adrian Boyle, president of the Royal College of Emergency Medicine.

"Over the last weekend, we've had one of the busiest weekends in terms of calls to 999, to NHS 111, and probably in terms of attendance to A&E departments," he tells BBC Radio 4's Today programme.

He says the big impact from yesterday's nursing strike is the reduced patient discharges from hospital, making hospitals "even fuller", and leaving little space for ambulances to offload.

The public are advised to only call 999 for life-threatening problems, and to use 111 online as a first port of call for everything else.

Rachel Harrison, national secretary of the GMB union - one of the three unions which have ambulance workers on strike today - says that Health Secretary Steven Barclay's comments about the ambulance strikes are "insulting".

Barclay wrote in the Daily Telegraph that unions had made a "conscious choice" to inflict harm on patients.

Harrison said: "It's actually quite insulting to our members and our NHS workers who get up, go to work every day and put patient safety first. They're the ones feeling physically prevented on a day to day basis from being able to do their jobs."

She says the "sad reality is" that patients "are being harmed every single day" even when workers aren't on strike.

Harrison goes on to say that the government has "failed" to make a pay offer to workers so far, and that the unions' doors are "truly open" to talking about pay.

Unions want a pay rise that is higher than the rate of inflation.

"It's not me, it's not the GMB, and it's not the other health unions that are refusing to talk about pay, it's this government," she says. "We are here, ready to talk... our door really is truly open and it's within [the government's] power to stop this dispute at any time."

Strike times depend on what area you're in. You can see what times strikes are affecting your area by visiting this page and scrolling halfway down to our interactive tool (Are unions on strike at your ambulance service?).

Image source, PA Media

Ambulance staff across most of England and Wales are going on strike today. The coordinated walkout involves the three main ambulance unions - Unison, GMB and Unite - and will affect non-life threatening calls.

The start times and lengths of the walkouts vary between unions and services, but all will last between 12 hours and 24 hours.

Some staff started striking at midnight, others at 6am GMT. Others - including staff in London - are starting the strike at midday.

Nine ambulance trusts are expected to be affected. The only service which will be completely unaffected is the East of England. There is no ambulance strike on the Isle of Wight.

The walkouts will involve paramedics as well as control room staff and support workers, with the military on standby to help out.

Eight ambulance trusts are expected to be affected on 28 December by another strike that will only involve members of the GMB union.

Image source, PA Media

As the strike begins, rhetoric from both sides - government and the unions - has intensified.

Writing in the Daily Telegraph, external, Health Secretary Steve Barclay says that organising sufficient cover to respond to the most serious emergencies has been made "almost impossible" by local arrangements being changed last minute.

"We now know that the NHS contingency plans will not cover all 999 calls. Ambulance unions have made a conscious choice to inflict harm on patients," he wrote.

But union boss Christina McAnea, from Unison, told Talk TV's First Edition, external that the government's refusal to open any kind of negotiations with them was irresponsible.

Asked whose fault it would be if people died, she said: "Absolutely the government's."

Trusts are concentrating on providing urgent and emergency care, particularly for life-threatening illnesses.

There are other ways people might get to hospital for non life-threatening conditions. These include:

• Taxis to transport less critically ill people to and from hospital where clinically appropriate
• Trusts might use the military to transfer patients with less urgent conditions to and from hospital (about 750 military personnel have been drafted in to help today)
• Using St John Ambulance and Community First responders

The emergency services will also be trying to ensure strong clinical triage in call centres and hospitals will be optimising discharges to create capacity.

Image source, Getty

Michelle Roberts
Health editor, BBC News online

Today’s industrial action will affect non-life threatening calls, meaning those who suffer trips, falls or other injuries may not receive the usual route of emergency care.

All category one calls - the most life-threatening such as cardiac arrest - will be responded to, while some ambulance trusts have agreed exemptions with unions for specific incidents within category two, which are serious conditions such as stroke or chest pain.

If someone has a life and limb emergency, they should call 999.

And if it's not that kind of emergency, they will be told to seek different advice.

If it is the kind of emergency where they would usually call 111, then they should do that, or they should consult a GP or pharmacist.

Image source, .

Ahead of today’s strikes, the NHS has issued some advice to the public:

• Use NHS services "appropriately" - this includes using 111 online as the first port of call for health needs and only using 999 if it is a life-threatening emergency
• Patients with non life-threatening conditions will have to wait longer than usual for an ambulance and may be asked to make their own way to hospital - although it is important that they get medical advice from 111 or 999 before doing so
• The public are asked to take "sensible steps" to keep themselves and others safe during the disruption, such as drinking responsibly or checking up on a vulnerable family member or neighbour
• The NHS says it will contact anyone whose medical appointment has to be rescheduled due to strikes. Anyone who has not been contacted is asked to attend appointments as planned
• People are reminded that general practice, community pharmacies, and dentistry are not impacted by the strikes

Welcome to our live coverage as we get ready for another day of strikes - this time by ambulance staff across most of England and Wales.

This strike, which is over a pay dispute, involves paramedics, call handlers and support workers who are represented by the unions Unison, Unite and GMB.

The military are on standby to help out.

Workers are striking at different times in different regions.

Officials say these walkouts will not affect life-threatening calls made to 999, but health leaders have nonetheless said patient safety can’t be guaranteed.

The unions have asked for above-inflation pay rises, which is more money than was recommended earlier this year by the NHS pay review body.

The government has so far said no. Stay with us for the latest developments throughout the day.