About 1,000 senior doctors have written to the British Medical Association (BMA) saying they are “extremely disappointed” with the stance taken on gender services.

The BMA has said it opposes a ban on puberty blocker treatments and wants the reforms following a recent official review to be put on hold, following a vote by members of its Council.

But organisers of the letter say the doctors, including some former heads of Royal Colleges, have backed the open letter.

It accuses the BMA of being “opaque and secretive”, with the policy not reflecting the views of the wider membership.

The BMA has responded by saying it wants to carry out its own “evidence-led evaluation of the issues…and the state of transgender healthcare in the UK today”.

A review of gender services by the leading paediatrician Dr Hilary Cass, commissioned by NHS England, was published in April.

It concluded that children had been let down by a lack of research and “remarkably weak” evidence on medical interventions.

Her report called for a move away from medical responses for children struggling with their gender identity, and the adoption of a broader based model incorporating better mental health support.

Shortly before the report was published, the one clinic offering gender services in England and Wales, the Tavistock in London, was closed.

NHS England said it would no longer support routine prescribing of puberty blockers, which the NHS used to prescribe as a way of halting puberty. This was followed by a government ban on the drugs.

In early August, NHS England announced its response to the main recommendations of the Cass Review.

This included setting up eight new centres to serve England and Wales by 2026, including two which are already running. Each will have a nominated paediatrician or psychiatrist with overall responsibility for patient safety.

Referrals will be made by mental health or paediatric services rather than directly from GPs. There will also be a clinical trial next year on the potential benefits and harms of puberty suppressing hormones.

There was a broad welcome from health leaders for the measures. However, the BMA has called for a pause to the implementation of the Cass Review’s recommendations and said it will carry out its own review of the findings.

The BMA, while welcoming news of next year’s trial, opposes the ban on puberty blockers and argues clinicians should decide on the treatment of patients.

Organisers of the letter to the BMA leadership say it has the support of about 1,000 doctors, more than half of whom are BMA members.

They say 23 former or current clinical leaders at Royal Colleges are among the supporters.

The letter says the Cass Review was right to conclude there was so little evidence about the “safety and efficacy” of puberty blockers that they should only be prescribed under research conditions.

It goes on to argue that the BMA was “going against the principles of evidence-based medicine and against ethical practice”.

In response, Prof Philip Banfield, chairman of the BMA Council, said that the points raised would be taken on board as part of the organisation’s evaluation of the issues.

However, he said that the decision by NHS England to stop routine prescribing of puberty blockers and then the government ban “goes further than any recommendation in the Cass Review”.

He added that the BMA Council had “concerns about the rapid, but selective implementation” of the review proposals.