The Professional Jockeys Association has called on the British Horseracing Authority to “bring to an end” its investigation into Bryony Frost’s allegations against fellow rider Robbie Dunne – because it believes a fair hearing has become impossible.

Documents were leaked to a newspaper, and published over the past two weeks, and the PJA believes the matter therefore cannot now proceed “however unsatisfactory that is”.

In the leaked documents, it emerged Dunne had been charged with  “conduct prejudicial to the integrity or good reputation” of racing. Days later, it was revealed a second complaint was made by a female rider to the BHA over a safeguarding incident involving a male jockey.

An investigation has been ongoing for more than a year – a length of time which the PJA also called “unacceptable”, adding that its members are “upset” because of the negative headlines created around their weighing-room culture.

The statement read: “The PJA has a policy of not commenting on ongoing investigations and has such a policy out of fairness, respect to the process and to natural justice being allowed to be served without prejudice. The PJA cannot therefore comment on the case specific details but must comment on the current, deeply concerning situation.

“The BHA has been aware of a potential data breach in relation to the leaked documents since August, and reported itself at that time to the Information Commissioners Office. It is vital that the investigation into the data breach is concluded as a matter of urgency, the cause of the data breach identified and anyone involved held to account for the distress caused.

“The length of time taken in bringing this case to a conclusion is unacceptable.  Now that material has been leaked to the media, and the information leaked is the charge letter and accompanying documentation that should only have been available to the BHA, Robbie Dunne and his legal advisers, a fair hearing is impossible. The matter cannot now be permitted to proceed – and we call upon the BHA to bring this matter to an end, however unsatisfactory that is.

“The PJA is aware that its membership is upset by the negative headlines about the culture in the weighing room that have been circulating this past week. The PJA understands and sympathises with their frustration, particularly from those female jockeys who have contacted us. We are grateful to them for respecting the process that must be allowed to conclude.

“The PJA published a Code of Conduct in May, which was the first of its kind in racing.  We expect our members to abide by this code.  We want to ensure that our sport welcomes everyone and we agree that people need to be held to account against a set of rules and codes of expected behaviour.

“We do not, however, accept the explicit and implied criticism of our membership as laid out in recent articles. The PJA does accept that there are ‘heat of the moment’ exchanges, not uncommon in sport, that are quickly resolved – and there may also be occasions when behaviours do fall short of the PJA’s Code of Conduct and the Rules of Racing ”

Paul Struthers, PJA Chief Executive, said: “Any individual subjected to behaviour that might constitute a breach of the Rules of Racing or the PJA’s Code Conduct must have the right to pursue a complaint, and that right must be respected. The PJA has no toleration of bullying and does not, and will not, stand idly by when it becomes aware of such conduct.

“When serious allegations are made it is vital that they are investigated thoroughly and speedily. Equally, an individual investigated for potential offences under the Rules of Racing is entitled to be subjected to a fair process and have a fair hearing.

“It is surely now impossible for that to happen in this case, however unsatisfactory that is for both parties.”

PA Media has sought a response from the BHA.