Video report by ITV News Political Editor Robert Peston
The head of the NHS has appeared to clash with Downing Street by saying it is "stretching it" to say the health service got more money than it asked for.
Simon Stevens, chief executive of NHS England, told to MPs on the Commons public accounts committee that it was correct that the NHS was getting an extra £20 billion over six years.
But he said that in the spending review, "it's a matter of fact that like probably every part of 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 and that it did not help anyone to "pretend that there aren't".
Last year, Prime Minister Theresa May said the NHS had got more cash than it asked for.
She said: "We have given the NHS more than the extra money they said they wanted for their five-year plan."
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 this figure has come under attack from MPs and commentators, who have accused the Government of changing the rules on how it calculates the funding figure.
Mr Stevens said it would be wrong to "conflate" the figures.
Mrs May's spokeswoman told a regular Westminster briefing that NHS chiefs had welcomed spending plans when they were set out.
She said: "The figures speak for themselves, and they will see an increase in real terms of £10 billion. 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.
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 added: "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.
"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."
Mr Corbyn recounted how a woman called Sian who works in the NHS and has a 22-month-old nephew saw him treated on two plastic chairs pushed together with a blanket because there were no beds.
He said: "Does the Prime Minister and the Health Secretary think this is an acceptable way of treating a 22-month-old?"
Mrs May replied: "I accept there have been a small number of incidents where unacceptable practices have taken place.
"We don't want those things to happen, but what matters is that the NHS looks into issues where there are unacceptable incidents that have taken place and then learns lessons from them."
She said over the few weeks around Christmas there was a single day when more people were treated within A&E than "had ever happened before".
She added: "This is the reality of the National Health Service."