Doctors have put themselves on a collision course with the coalition by declaring they have no confidence in the health secretary, Jeremy Hunt, over his handling of the NHS.

The British Medical Association's annual conference endorsed by an overwhelming majority a motion expressing no confidence in Hunt on Monday. It came after a succession of speakers accused Hunt of "denigrating the NHS" and heavily criticising health professionals.

Delegates supported a motion proposed by Dr Jacky Davis, a hospital consultant and member of the BMA's ruling council, which took Hunt to task for claiming there was too much mediocrity in NHS care and too many hospitals were "coasting".

The leader of the doctors' union, Dr Mark Porter, broke with tradition by endorsing the move, which risks straining the BMA's relations with the Department of Health.

No vote needed to be taken at the BMA's annual representative meeting in Edinburgh because antipathy towards Hunt – who has made a succession of speeches lambasting standards of care and NHS staff, including GPs and nurses – was so widespread.

Proposing the motion, Davis said Hunt was leading the government's "ideological attack on the service and on staff".

The NHS had been "wrecked" by the coalition, she claimed. "Leading the attack has been the health secretary. His main purpose seems to be criticising the service and undermining the staff.

"He is at the forefront of a new political blame game, blaming frontline NHS staff for the predictable chaos resulting from his government's reforms and cuts," she said to applause.

It is the second year in a row that doctors' representatives have signalled their lack of faith in the health secretary after doing the same last year with Andrew Lansley, Hunt's predecessor and the architect of the government's controversial shakeup of the NHS in England.

Hunt has only been in the job since last September. Initially mollifying to a medical profession which viewed Lansley with suspicion and alarm, Hunt has alienated key groups of NHS staff by attacking nurses for giving poor care and family doctors for abandoning out-of-hours care.

A motion submitted by the BMA's division in Islington, north London, said the conference "notes with disgust the secretary for health's attack on hospitals, accusing hard-pressed NHS staff of 'mediocrity and coasting'. This meeting observes that the current secretary for health appears to be denigrating the NHS at every opportunity."

The conference ignored arguments that "personal invective" against a minister could backfire on the BMA. Porter said that while it was traditional for the union's leader to argue that it should concentrate on policies rather than personalities, Hunt was proving to be no better than Lansley.

"This present coalition government goes out of its way to act against the interests of patients," said Porter, who joined in the applause for Davis's speech.

Hunt did not respond to the BMA's move. But the Department of Health defended his right to seek the highest possible standard of care for patients and cited Robert Francis QC's report into the Mid Staffs scandal as proof of how the NHS's culture needed to change radically.

A spokeswoman said: "It is completely right that the health secretary demands the best possible care for patients. Following the findings of the Francis inquiry and other recent reports, it is clear that the culture of the NHS needs to change and it is disappointing that the BMA union still doesn't accept that."