NHS doctors are being forced to choose who lives and who dies as a shortage of intensive care beds means terminally ill patients are being refused life-saving surgery.

Oesophagus cancer sufferer Simon, 67, is one patient whose missed operations were exposed by film-makers.

He has twice had operations to remove his tumour cancelled to make way for emergency procedures, and was told he and a critically ill 78-year-old were in direct competition for an intensive care bed.

"If they die then the bed is available for me, but if not they've got the bed," he said during filming for the documentary, which is broadcast this Wednesday on the BBC. "[I feel] guilty, actually."

Jeremy Hunt on NHS mortality rates

The film-makers secured unprecedented access to five NHS hospitals across six weeks, and revealed the human cost of wide-spread bed shortages across the NHS.

In St. Mary's Hospital in London, where Simon is awaiting treatment, there are only sixteen intensive care beds. Simon Ashworth, who heads the over-stretched unit, said: "Everyone thinks what they're doing is important and, guess what, everybody's right."

Figures show A&E departments shut their doors to patients more than 140 times in December, while a third of NHS trusts in England have issued alerts as they are struggling to cope with demand, according to the Nuffield Trust.

Fifteen hospitals across England were running at 100% capacity in the weeks running up to Christmas, according to an official report.

In pictures: Junior doctors protests in UK Show all 10 1 /10 In pictures: Junior doctors protests in UK In pictures: Junior doctors protests in UK 20,000 Junior Doctors marched through central London in protest at the new contract changes the government is trying to impose which they say will be unfair and unsafe In pictures: Junior doctors protests in UK Junior doctors protest in London In pictures: Junior doctors protests in UK 4 year old Cassius takes part in a demonstration in Westminster, in support of junior doctors over changes to NHS contracts, London In pictures: Junior doctors protests in UK Protest over proposed changes to junior doctors' contracts, Leeds In pictures: Junior doctors protests in UK Junior doctors and NHS staff protesting against the health service cuts and the proposed contract changes offered by the government outside Parliament In pictures: Junior doctors protests in UK Junior doctors and NHS staff protesting against the health service cuts and the proposed contract changes offered by the government outside Parliament In pictures: Junior doctors protests in UK Over 5000 junior doctors rallied in Waterloo place, before marching through Whitehall and onto Parliament Square, in opposition to Jeremy Hunt's new working conditions for doctors In pictures: Junior doctors protests in UK Demonstrators listen to speeches in Waterloo Place during the 'Let's Save the NHS' rally and protest march by junior doctors In pictures: Junior doctors protests in UK Junior doctors marched in London to highlight their plight In pictures: Junior doctors protests in UK A protester at a demonstration in support of junior doctors in London

Speaking to the Independent, trade union leader Len McCluskey said: "Health economists have consistently said that by forcing the NHS to make £20 billion in savings by 2020, the government is driving this service into crisis.

“The government knows all too well that the funding for the service falls far short of what is needed to meet the challenges presented by the monstrous debts carried by hospital trusts, from an ageing population and from the pitiful absence of a reliable, decent social care service, which is urgently needed to take the pressure off the frontline NHS.”

Meanwhile, Prime Minister Theresa May was forced to deny a warning from British Red Cross that hospitals are facing a “humanitarian crisis” after the organisation stepped in to support the overstretched health service.

And Health Secretary Jeremy Hunt has also been on the defensive. Quizzed about the BBC documentary on Radio 4, he said "“It’s an unspeakable tragedy when something like that happens. There are massive pressures in the NHS but what I don’t want to see is a return to the bad old days when people are waiting too long for their operations.”