The head of the NHS has gone into battle with Theresa May over NHS funding, saying it is "stretching it" to say it got more money than it asked for.

Simon Stevens, chief executive of NHS England, said an extra £10bn was being made available to NHS England over the course of six years but overall the health service had "got less" than set out in its five-year plan.

His comments contradict those of the Prime Minister, who has insisted the NHS got all it wanted in the funding settlement.

Speaking to MPs on the Commons public accounts committee, Mr Stevens said: " Well it's right that by 2020 NHS England will be getting an extra £10bn over the course of six years.

"I don't think that's the same as saying we are getting more than we asked for over five years because it was a five year forward view, not a six year forward view.

"And over and above that we've obviously had a spending review negotiation ... it's a matter of fact ... that like probably every part of the public service we got less than we asked for in that process. It would be stretching it to say we got more than we asked for."

Mr Stevens also said there were "very substantial pressures" on the NHS, adding: "I don't think it helps anyone to pretend that there aren't.

"That's not a new phenomenon, it's a phenomenon that's intensifying."

Over the weekend, Mrs May said the NHS had got what it asked for in its five-year plan.

She said "we gave them that funding, in fact we gave them more funding than they required. So funding is now at record levels for the NHS, more money has been going in."

In October, MPs said Mrs May's claims that the Government was putting £10bn extra into the NHS were untrue.

They said the £10bn figure could only be reached by adding an extra year to the spending review period, changing the date from which the real terms increase is calculated and disregarding the total health budget.

Mr Stevens's comments come after The Times reported that Number 10 aides have accused Mr Stevens of not being "enthusiastic" enough, although Downing Street has dismissed the report.

Speaking to MPs, Mr Stevens appeared to address this phrase.

Asked about £5bn cuts to social care funding, he said: "I've been running a little campaign against doing that ... enthusiastically I might add."

Mr Stevens used the MPs' session to say nobody should pretend there is no funding issue in the NHS.

He said: "In the here and now there are very real pressures ...This is not because hospitals are being feckless. It doesn't help anybody to pretend there aren't finance gaps."

He added: " In 2018/19, in real terms, NHS spending is going to go down - 10 years after Lehman brothers and austerity began."

The Department of Health's permanent secretary, Chris Wormald, told MPs it was delivering the election pledge to give the NHS £10bn.

But Mr Stevens appeared to contradict this and said it would be wrong to conflate figures.

Mrs May's spokeswoman told a regular Westminster briefing that NHS chiefs had welcomed spending plans when they were set out.

"The figures speak for themselves, and they will see an increase in real terms of £10bn. And at the time the NHS England chief executive said 'the settlement is a clear and highly welcome acceptance of our argument. Our case for the NHS has been heard and actively supported'."

Mr Stevens also used the meeting to hold up a copy of the Daily Mail with an article saying Britain spends less than the rest of Europe on things like doctors and beds.

It came after Mr Wormald said total spending on health is around the average for the OECD.

Mr Stevens said the OECD includes countries like Mexico, and Britain actually spends less than countries it compares itself to, including 30% less per head than Germany.

Shadow health secretary Jonathan Ashworth said Mrs May's " argument has now been blown out of the water by two top NHS chiefs who have starkly laid out the truth: the NHS is facing financial crisis under the Tories."

Earlier, Mrs May exchanged blows with Labour leader Jeremy Corbyn over the state of the NHS.

It comes after an intense week during which organisations including the Royal College of Physicians have written to Mrs May saying the NHS is underfunded and people's lives are at risk.

Its head, Professor Jane Dacre, has said the NHS is experiencing its worst winter crisis.

Mrs May said in the Commons there had been a "small number of incidents of unacceptable practice" in the NHS as she sought to defend the Government's handling of the issues.

She said : "We acknowledge that there are pressures on the health service, there are always extra pressures on the NHS in the winter, but we have the added pressures of the ageing population and the growing complex needs of the population."

She said: "The Government has put extra funding into the health service ... 2,500 more people are treated within four hours every day in the National Health Service - that's because of the Government putting in extra funding and the hard work of medical professionals."

Figures out on Tuesday showed record numbers of people have experienced long waits in A&E.

Clare Marx, president of the Royal College of Surgeons, applauded Mr Stevens for speaking "truth to power" about the pressures on health and social care sectors.

She said: "The NHS and our care homes have now passed a tipping point where they can no longer keep up with the demand we face throughout the year.

"The stresses being reported in A&E are just one aspect of what is faced on a daily basis in every part of the health service.

"With Brexit and an uncertain economic outlook facing the country, we fully understand why there may be a reluctance to provide further funding.

"However, it is clear that we can't go on fire fighting and rapid support is needed while being clear about what the NHS and care services can or can't provide. More money isn't the only solution, but it is an important part of it."

Ms Marx also welcomed news that the Cabinet Office is reviewing how to make long-term social care funding sustainable, and called for the same to happen with the health service.