The ARB has issued an injunction against rebel board member Ian Salisbury in an effort to end the publication of details of confidential legal advice.
The board delivered the legal papers after repeatedly warning Salisbury to take down the details of a lawyer's opinion on Part 3 qualifications posted on his website.
The Oxford-based practitioner has repeatedly refused requests to stop publicising details - which the board claims are misinformed - from the legal document.
Salisbury has, however, rejected any accusations that he has done anything wrong and has instead vowed to fight the injunction.
'I consider this bullying as I do not think that there is anything wrong with what I have done, ' he told the AJ. 'I have taken legal advice and consider this worth fighting. There seems to me to be no reason why they should have issued an order and it really is extremely frustrating, ' Salisbury added.
And Salisbury has won the support of former RIBA president Rod Hackney, a long-term critic of the ARB. 'There is no justification for this gagging order, ' he said. 'I believe Salisbury is in the right and should be praised for carrying out his convictions.
'What will the membership make of the way that an elected member of the board is being treated?' Hackney added.
But ARB chief executive Robin Vaughan said the board's actions were justified. 'We felt this confidential and legal advice should not be published because it is confidential and legal, ' he said.