“We thought the original judgement was pretty strong and we did think the appeal was unusual,” he said. “But the Court has confirmed the view that we’ve had ever since this litigation began four-and-a-half years ago.”

Stack commented on the irony that Keddies, which brought a professional negligence claim against Stacks in 2007, has been found professionally negligent itself by the Court of Appeal.

The judgement handed down by Justice Beazley on Friday (17 August) stated that Keddies solicitors did not believe that the case against Stacks had reasonable prospects of success and upheld Colefax’s ruling that Keddies had breached the Legal Profession Act.

Costs have been awarded to Stacks. While the final figure has not yet been agreed to or assessed, “it will be significant”, claimed Stack.

In the judgement document, Beazley reiterated Colefax’s finding that Keddies’ conduct involved “many disturbing departures … from acceptable and proper conduct as a solicitor”. She also criticised Keddies’ solicitors for paying “inadequate” attention to the professional negligence proceedings and for ignoring the advice of the firm’s own barrister, Kelvin Andrews.

In a 2007 letter to Keddies, Andrews stated that the client “had severe difficulty in proving [a] claim", "[would] not succeed in the proceedings” and that “this [was] not a matter … that I would recommend should ever be allowed to go to court”.

Beazley also claimed there was no evidence that Keddies had obtained adequate instructions from its client.

“It is one thing to contend that a witness does not ‘come up to proof’ in the witness box or is otherwise found wanting. It is another to fail to ask a client a fundamental question upon which the claim is based,” she stated.

Keddies initiated a suit against Stacks in 2007 on behalf of its client Andrew Marshall, whose son Matthew was killed in a car accident.

Stacks had represented Marshall in his claim for damages for nervous shock against Allianz, the insurer of the driver deemed liable for the crash.

Recently acquired by Slater & Gordon, Keddies is no stranger to criticism. Former solicitor Russell Keddie was struck off the legal roll earlier this year after being found guilty of professional misconduct for overcharging clients.

Keddie and two former partners, Scott Roulstone and Tony Barakat, were ordered by the courts to pay back around $4 million to former clients.