DOCTORS have warned that hospital waiting lists will "climb exponentially" and some services will become "impossible to run safely" amid an exodus of senior staff hit by huge pension tax bills.

The scale of the crisis is laid bare today with half of the consultants, GPs and other medics who responded to a survey by BMA Scotland saying they were now cutting back their working hours or shunning overtime designed to bring down spiralling waiting lists because doing so would actually cost them money.

One medic said they had calculated that taking on extra work would see them paying £2 to the taxman for every £1 earned.

Among the 354 clinicians polled to date, 46 per cent had already received a tax bill. The average cost was £18,500.

Respondents said the policy had crushed morale and "done more to create a rush to retirement than any amount of work pressure".

Analysis: A pensions policy designed to hammer the rich is at risk of harming the sick  

Nearly a quarter (22%) of doctors said they had either taken, or were considering, early retirement from the NHS because there was no financial incentive to continue.

There are concerns that the situation facing consultants will derail the Scottish Government's attempts to meet waiting times targets for cancer and elective surgeries by 2021 unless urgent action is taken to mitigate or reverse the "punishing" tax regime, set by the UK Treasury.

Nearly 44 per cent of GPs who responded also said they were reducing or opting out of out-of-hours work as a direct result of pension tax charges.

It comes just weeks after NHS Greater Glasgow and Clyde was forced to temporarily close four of its five out-of-hours GP centres amid a crippling staff shortage.

Case study: 'I'm cutting hours - patients will have to wait longer for cancer surgery'

Andrew Buist, Chair of BMA Scotland’s General Practitioners Committee said the findings must be a "wake-up call" to politicians.

He said: “We all know the deep seated problems that exist around recruitment and retention of GPs and there can be no doubt this is making the position substantially worse.

"It is incredibly frustrating, that at a time when we need to focus entirely on implementing the new GP contract, issues like this should threaten to undermine the progress we are making.

"For example, it is absolutely no surprise that GP out of hours services are struggling to cope and fill shifts, when GPs who volunteer may face being financially penalised as a result.”

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The interim findings are based on responses gathered between May 23 and June 10, primarily from senior doctors at the middle or latter stages of their career.

The survey is ongoing, but the results so far found that 37% of medics believe the impact of the pension tax will have a “significant impact on urgent and emergency care” in Scotland by leaving frontline services “uncovered”.

More than 26% of doctors said the impact would be so bad it would be “likely to collapse an area of service”.

Responses included a warning from one medic that the situation would be “disastrous to services that need these senior people to manage”, while another warned that “waiting times will rise exponentially as a result”.

Another doctor highlighted the risk to out-of-hours services, stating: “The service is extremely vulnerable to this reduction in manpower and it will make the service impossible to run safely.”

The bizarre tax penalties have come about mainly due to the introduction of a tapered annual allowance in 2016 has reduced the tax-free amount that anyone earning over £110,000 can save into a pension each year.

It was designed to stop the wealthy benefitting disproportionately from tax breaks, but has ended up with many doctors paying more in taxes than they have received in overtime pay.

Lengthy delays in tax bills being sent out has meant that many doctors have only begun to realise the scale of the problem in the past year.

Read more: Should doctors quit the NHS over 'punitive' tax measures 

Today’s findings for Scotland comes as data covering England and Wales revealed that the number of senior doctors taking early retirement south of the Border has tripled in a decade, from 384 in 2008/9 to nearly 1000 last year.

Simon Barker, chair of BMA Scotland’s Consultant Committee said: “No-one would expect anyone, in any profession, to continue with a working pattern that could leave them substantially worse off.

“Through this survey, doctors are very clearly telling us that they are being left with no option but to cut their working hours, in some cases because it’s actually costing them more money than they are earning.

“This loss of capacity in the workforce will inevitably have serious implications for the care NHS services are able to provide.”

Earlier this month, UK Health Secretary Matt Hancock announced a consultation on proposals to alter the regime.

The so-called '50:50' alternative would allow clinicians to halve the amount they save into their pension in exchange for halving the rate at which their pension grows.

Mr Hancock said this would provide "greater flexibility" and "a deal that’s fair to doctors, taxpayers, and the patients they care for".

Critics said it devalues doctors' pensions and "punishes them for a crisis not of their making".

Campaigners have urged the Scottish Government to do more in a bid to mitigate the worst effects of the pension tax charges on Scotland's medics.

A Scottish Government spokesman said: “The rules regarding pensions taxation are reserved to the UK Government and the Health Secretary has written to the Chancellor urging a quick resolution to avoid loss of expertise and call for an urgent review. 

“The Scottish Government and the Scottish Public Pensions Agency (SPPA) continue to work with stakeholders, including the BMA and employers, to better understand how these rules are impacting on doctors’ working hours and Out of Hours services.

"We welcome the BMA findings, which along with the NHSScotland Board surveys, will help develop solutions to mitigate the impacts of the Annual and Lifetime Allowances.”