The prime minister's comments came less than a day after NHS England announced that it had ordered acute trusts to postpone all elective procedures until the end of January - a move that GP leaders say will leave practices struggling to manage patients waiting longer for hospital care on top of the expected seasonal rise in illness.
BMA leaders warned that despite the prime minister's claims, the NHS was 'in the grips of another winter crisis' - warning that politicians were failing to provide the long-term investment the health service needed to become sustainable.
However, the prime minister said on Wednesday that the NHS is 'better prepared for this winter than ever before'. Ms May pointed to the £335m winter pressures fund unveiled by chancellor Philip Hammond in his autumn budget, adding that there were 'more beds available across the system' and delayed discharges of elderly patients had been reduced.
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But she acknowledged: 'I recognise that for those people who have had their operations cancelled this is disappointing, it's frustrating, and we will ensure that those operations are put back as soon as possible.'
Health secretary Jeremy Hunt sought to justify the decision to halt elective care, telling Sky News that if operations had to be cancelled it was better done in a planned way. He also apologised to anyone whose operation had been cancelled, saying: 'I don't belittle that in any way.'
Labour shadow health secretary Jonathan Ashworth said Ms May was 'out of touch'. 'Yet again Theresa May reveals how entirely out of touch she is,' he said. 'Next, she will be trying to lecture patients that "nothing has changed".
'The reality is we see hospitals at full capacity, ambulances backed up, cancelled operations and patients waiting for hours on trolleys.
'Instead of burying her head in the sand, Theresa May needs to explain why she has allowed underfunding and cuts to health and social care to continue.
BMA representative body chair Dr Anthea Mowat said: 'The NHS is in the grips of another winter crisis, as patients face long delays in care, operations are cancelled and staff find themselves working under extremely difficult circumstances.
'What is happening in our A&Es is symptomatic of pressures across the entire system. Hospitals are at capacity, GP surgeries are full, and a shortage of social and community care means that many patients who no longer need to be in hospital can’t be discharged as there is simply nowhere for them to go.
'Short-term fixes, however well meaning, will only get us so far. Each winter the pressure on the NHS worsens, and politicians are not taking the long-term view needed to ensure the NHS can keep up with rising demand. We have to look again at NHS funding, which remains well below what other comparable European countries spend on healthcare, to ensure the NHS has the staff and the capacity needed to deal with the pressures it faces year in, year out, but which are compounded during the winter months.'
NHS Confederation chief executive Niall Dickson said: 'Our members warned repeatedly that this winter was likely to put an already stretched system under intolerable strain.
'In many ways the health service in England is better prepared than ever before, but that does not prevent a situation where hospitals are having to cope with unsafe levels of bed occupancy. The numbers of people needing to be admitted has grown and the shortages in the community too often mean it is impossible to secure appropriate care for patients even when they are better.
'There was some extra money in the budget but £335 million was frankly too little too late – and it did nothing to ease the social care crisis.'