A lawyer acting for former chancellor Nadhim Zahawi improperly attempted to restrict a tax expert from discussing communications regarding the politician’s failure to pay tax, a tribunal has ruled.

Ashley Hurst, of Osborne Clarke law firm, faced a solicitors disciplinary tribunal over allegations that he sent an email and letter to Dan Neidle, founder of Tax Policy Associates, in July 2022 in which he “improperly attempted to restrict Mr Neidle’s right to publish that correspondence and/or discuss its contents”.

The communications asked Mr Neidle to retract claims he had published that Mr Zahawi lied about failing to pay £3.7 million in tax, and also not to publish the correspondence.

If I had not been able to publish, Mr Zahawi would still be in politics and might even be prime minister

On Friday, the tribunal ruled that the allegation relating to an email sent on or around July 16 2022 was proven on the facts and that Mr Hurst had breached paragraphs of the Solicitors Regulation Authority (SRA) Code of Conduct for Solicitors.

Mr Hurst was fined £50,000 and ordered to pay costs of £260,000.

A second allegation relating to a letter sent on or around July 19 2022 was found not proved, the tribunal ruled.

Delivering the tribunal’s findings, Alison Kellett, chair of the panel, said: “Despite the high profile of the client in this case, a former chancellor of the Exchequer, this is fundamentally a case focusing on a straightforward question – should an experienced solicitor, a partner in a city firm specialising in defamation and reputation management, have sent two specific communications containing the words that they did to an activist blogger?

“Did he correctly label those communications, and did he try and stifle the publication of them by threatening the recipient of serious consequences if he did so? Can his conduct be justified?”

She went on to say that in relation to the first allegation – regarding the email on or around July 16 – the panel found it “proven on the facts”.

The email, marked “without prejudice”, said Mr Zahawi considered Mr Neidle “overstepped the mark today by accusing him of lying to the media and the public” and conveyed an opportunity for Mr Neidle to “retract your allegation of lies in relation to our client”.

It also said: “It is up to you whether you respond to this email but you are not entitled to publish it or refer to it other than for the purposes of seeking legal advice. That would be a serious matter, as you know. We recommend that you seek advice from libel lawyer if you have not done already.”

We are extremely surprised and disappointed with this outcome in light of the legal position and evidence heard at the tribunal

Giving evidence to the disciplinary panel on Monday, Mr Neidle said he took the email to mean that he could not publish the fact that he received a message from the then-chancellor’s lawyers ordering him to retract the claim and that “there would be serious consequences if I did”.

“I thought that was shocking,” he said, adding that he was not sure if it was a threat of civil proceedings on the basis of breach of confidence or a threat to take it to the SRA or both but he “knew it was a threat”.

Mr Neidle eventually published both the email and the letter from Mr Hurst, crediting those publications with bringing a “great deal” of attention to Mr Zahawi’s tax affairs.

“Ultimately (it) led to Mr Zahawi’s undoing when the fact of his secret settlement became public,” he said.

“If I had not been able to publish, Mr Zahawi would still be in politics and might even be prime minister.”

Mr Neidle called the email a “request that Mr Zahawi gets exactly what he wants and I get nothing” and said he did not read it as an attempt to settle.

A spokesperson for Osborne Clarke said: “We are extremely surprised and disappointed with this outcome in light of the legal position and evidence heard at the tribunal.

“We will await the detailed reasons of the tribunal before commenting further.”