More than 100,000 doctors are to be balloted on industrial action over pensions in a dramatic escalation of the bitter dispute over the government's controversial public sector reforms.

Leaders of the British Medical Association (BMA) today decided that doctors and medical students should vote on whether to take action - the first ballot if its kind since the 1970s.

However the BMA ruled out strikes in a move designed to limit the impact on patients across the country.

A BMA spokeswoman said no timetable has been set yet for when the ballot will take place and officials would be working on details in the coming days.

The decision follows overwhelming rejection by doctors and medical students of the "final" offer on pensions.

The BMA said the changes would see younger doctors paying more than £200,000 extra over their lifetime in pension contributions and work eight years longer, to 68.

Officials have urged the government to reopen talks with the health unions, but said neither the Treasury or the Health Department had signalled any change to their position.

Dr Hamish Meldrum, chairman of the BMA council, said: "Doctors are not asking for special treatment - quite the opposite. Just four years ago, NHS staff agreed to major reform of the NHS pension scheme to make it fair, affordable and sustainable. Now the Government wants to go back on that deal.

"The NHS pension scheme is in a strong financial position and the economic downturn does not affect that as staff have already accepted responsibility for covering any future cost increases."

The BMA accused the Government of failing to return to meaningful talks on NHS pensions despite urging ministers to resume negotiations.

Strike action was ruled out as part of a commitment to ensuring that whatever action is taken does not cause harm to patients, said the BMA.

Detailed plans will now be drawn up on the timing of the ballot and the nature of any industrial action that would take place in the event of a "yes" vote.

More than 80% of the 46,000 members who responded to a BMA survey in January said the Government's offer should be rejected, and nearly two thirds said they were willing to take industrial action to achieve a fairer deal.

Health Secretary Andrew Lansley told the BBC that he was disappointed with the decision, because in negotiations before Christmas heads of agreement had been reached with all the NHS trade unions except Unite.

"I felt we had secured for the NHS, and staff of the NHS, the sort of pension they could rely upon, and feel confident in, in the future."

He said the 2008 scheme had not been sustainable in the long term, and was not fair to taxpayers.

"All we are asking is that normal pension age in the NHS scheme for doctors should be in line with the state pension age," he said.

A consultant retiring at 68 under this scheme would be retiring with a pension of £68,000 a year. "I think that's a pension reflective of the value we attach to doctors, and I hope they will recognise that."

He dismissed a suggestion that the NHS was "in a mess".

"I don't accept that for a minute. The NHS is its staff and the services that are being provided, and the staff are doing a fantastic job.

"Waiting times are down, mixed sex accommodation is being cut by 95%, there's over 900,000 more people having access to NHS dentistry, hospital-acquired infections like MRSA and clostridium difficile are at record lows, and across the NHS money is being saved while delivering that fantastic performance. We've had efficiency savings of over seven billion already.

"It is in order to maintain that performance and deliver a better service in the future that we are intending through the reforms not only to empower patients with better information and choice, but to empower frontline staff, doctors and nurses themselves, with greater ability to deliver the services they want, to design the services they want, that are in the best interests of patients."