Transgender campaigners are calling for an end to a ‘witch hunt’ against a British doctor accused of errors in treating gender reassignment patients.

The General Medical Council probe into the practice of Dr Richard Curtis was launched after allegations over his prescription of hormone therapy drugs and a serious complaint by one patient who had a double mastectomy but later regretted the decision.

He is also accused of breaching restrictions placed on his private clinic in London by the Medical Practitioners Tribunal Service (MPTS), which include a ban on prescribing hormone treatment for trans patients before they have undergone a mental health or psychological assessment.

However, the investigation has sparked anger among many in the UK’s trans community who argue Dr Curtis’s Marylebone practice is a ‘lifeline’ to those seeking transition.

An online petition on website Activism.com accuses the GMC and the MPTS of a ‘witch hunt’ fuelled by the national press and calls for a fair and balanced hearing which includes testimonies from other present and former patients who have been helped by the doctor.

Karen Richards, a patient of Dr Curtis, set up a Facebook group urging the trans community to support the GP.

‘Dr Curtis is the only alternative for patients in the UK that the NHS has let down through cuts and a massive treatment waiting list that is getting longer and longer,’ Richards writes on the group’s wall.

‘The alternative these people face is to buy hormones and anti-androgens over the internet via dubious websites and with no monitoring whatsoever.’

‘If we lose his facility, there are hundreds of trans people who would be up the creek without a paddle because the NHS does not have the resources to treat every single trans person who applies for transition,’ Richards told Gay Star News.

She added: ‘It can currently take up to six years to get treatment on the NHS and that’s a huge gap in people’s lives.’

Daniel Hall, another patient of Dr Curtis, wrote on the Facebook page that the GP did not mislead him with ‘false encouragement’ and warned him of ‘every possible pitfall’.

But one member of the group, Susan Marolyn Collier, slammed accusations that the GMC’s investigation was a witch hunt.

She wrote: ‘From what I have read only the patients have made allegations.

‘I want proper and well reported investigations and it would appear we are getting this.

‘What we are seeing in this group is lots of people successfully treated but those (who) have been treated unsuccessfully should have their voice too.’

The GMC investigation has re-ignited debate on the treatment of transgender people on the NHS.

In response, a Twitter hashtag was started by transgender Liberal Democrat councillor Sarah Brown to allow trans people to tell their stories of how they were mistreated by doctors.

#TransDocFail opened the floodgates to alleged accounts of abuse and discrimination.

Stories include how one follower was called a ‘shemale’ by a gender specialist psychotherapist, another told by an NHS Direct doctor that she was an ‘abomination’ and one trans patient who was refused emergency access to gynaecology for over a year.

Restrictions on Dr Curtis’s practice will remain in place until the GMC publishes the results of its investigation. If the complaints are upheld, the case will return to the MPTS for a further hearing.

A spokeswoman for the Medical Defence Union, which is representing Dr Curtis, told The Guardian the GP was unable to comment on any of the allegations ‘because of the ongoing investigation and his duty of patient confidentiality’.