Resident doctors have begun a five-day walkout in England in a row over pay - despite pocketing rises worth 28.9 per cent over the past three years.

The 13th walkout, by British Medical Association (BMA) members in both emergency and non-urgent care, began at 7am today and will last until 7am on Wednesday. 

Health leaders have warned the NHS may have to cut frontline staff and perform fewer operations and scans to cover the cost of ongoing doctors' strikes.

The industrial action is expected to blow a £240million hole in the health service budget, as hospitals are forced to cancel appointments and pay consultants inflated overtime rates when covering for junior colleagues, who are demanding another 26 per cent.

Health secretary Wes Streeting has accused the British Medical Association, the doctors' union, of acting like a 'cartel' and trying to hold the country to ransom over the extortionate bill.

Now, the NHS Confederation and NHS Providers, which represents healthcare organisations, say 'constrained' NHS budgets can no longer absorb this cost and cuts will have to be made if the Treasury does not bail them out.

They yesterday pleaded with the BMA to call off their 'disproportionate' strike, stressing it will cause 'excessive disruption' to patients, who will have to wait longer for care.

The last time resident doctors went on strike, over 54,000 procedures and appointments needed to be cancelled or rescheduled, despite the NHS maintaining 93 per cent of its planned activity.

Sir Jim Mackey, chief executive of NHS England, has written to trust bosses urging them to maintain 95 per cent of non-urgent care this time around - only rescheduling appointments and operations 'in exceptional circumstances to safeguard patient safety'.

However, NHS Confederation and NHS Providers said it is still likely that tens of thousands of patients could have their appointments, tests or operations cancelled or delayed if surges in demand require staff to prioritise urgent and emergency care.

The early flu season could further exacerbate these pressures, they added, with higher demand and increased staff sickness making it more difficult to fill rota gaps.

This risks jeopardising progress against key waiting time targets just as new figures show the NHS waiting list fell in September after three successive monthly rises.

Matthew Taylor, chief executive of NHS Confederation, said: 'There is no doubt that patients will bear the brunt of this disruption, with tens of thousands of tests, appointments and operations likely to be delayed or cancelled.

'NHS leaders understand how frustrating this will be for them being left waiting in pain or discomfort, not knowing when their treatment will be rescheduled.

'With flu already beginning to bite there is a real risk that these strikes will leave the NHS limping into a very difficult winter at a time when it is trying to recover performance and implement vital long-term reforms.

'But industrial action is also having a major financial impact on the NHS, with the last five-day walk out estimated to have cost a staggering £300 million.

'These costs are not included in the health service's budget, which is already very tight given the strain on public sector finances.

'This means that more strikes will blow further holes in these constrained budgets and could result in leaders having to cut staff or reduce service levels in order to balance the books.

'The BMA must recognise that these strikes are disproportionate, given the current financial environment and the fact resident doctors have already had one of the biggest pay rises in the public sector.'

The BMA yesterday said doctors must not be called off picket lines to cover planned NHS work during the strike.

The union said it would not agree to such 'derogations' unless NHS trusts have already cancelled planned activity and 'incentivised' other medics to provide cover.

Dr Tom Dolphin, BMA council chair, and Dr Emma Runswick, deputy chair, told hospital leaders in a letter that derogations are 'not in place to avoid disruption caused by industrial action but to ensure that in unexpected and extreme circumstances patients will continue to receive safe care'.

The letter said: 'Derogations will not be granted if planning has not occurred to incentivise non-striking doctors to cover emergency work, or if non-emergency work is continuing.'

Sir Jim has told hospital bosses that that if non-striking doctors provide cover during the strike, trusts 'should not adopt the BMA's rate card'.

The BMA's consultant rate card for working outside contracted hours sets a fee of £188 per hour for weekdays from 7am to 7pm, and £250 per hour for 7pm to 11pm.

Weekends are 7am-11pm for £250 per hour, and overnight shifts of 11pm to 7am are £313 per hour.

Daniel Elkeles, chief executive of NHS Providers, said patient safety is the number one priority, adding: 'Derogation requests during strike action aren't made lightly.

'These requests are initiated by trust-based medical directors, who are senior clinicians acting in good faith, to keep patients safe when unexpected and extreme circumstances arise during strikes.'

Mr Streeting last night said the blame for the 'needless' strikes 'lies squarely with the BMA' who refused to put his improved offer of more specialist training places and help with exam fees to its members.

Appealing directly to medics, he said: 'I urge resident doctors not to follow the BMA out on strike, come to work to give your patients the care they need, and let's continue rebuilding our NHS.'

However, Dr Jack Fletcher, chair of the BMA's resident doctors committee, accused NHS managers of 'emotionally blackmailing frontline staff who are taking legitimate industrial action to defend their pay and conditions, and fight for employment'.

He said that strikes 'have not come out of the blue', adding: 'What has been offered so far still leaves thousands of resident doctors without a role this year, and the Government seems determined to cut pay even further next year.'

Dr Fletcher said 'any resident doctor' would challenge the narrative that the NHS is 'somehow turning a corner'.

'We have doctors sitting on bins because there aren't enough chairs, patients routinely being seen in corridors, A&E waits through the roof and rota gaps are an accepted norm,' he said.

'We cannot let the Government and managers gaslight the public into putting the blame for these system-wide failures at the doors of hardworking doctors who are standing up for their profession and the future of the health service.'

The BMA's current mandate for strike action runs out in January after which it would need to ballot members.

NHS England is urging patients to continue coming forward for care and attend any planned appointments unless they hear otherwise.

Patients who need emergency help should continue to use 999 or A&E as normal, while NHS 111 is also available alongside usual GP services.