The man known as Mr Loophole - one of the highest-profile lawyers in the country - has been condemned for "sharp practice" by the High Court.
Sir John Thomas, president of the Queen's Bench Division, has criticised Nick Freeman over the methods he has used in the case of Zafar Ali, of Sudbury Hill, Wembley, north west London.
Ali pleaded guilty at Crawley Magistrates' Court in May last year to driving a Porsche at more than 117mph on a dual carriageway section of the A23, well in excess of the 70mph speed limit.
The prosecution was not represented at the hearing. Ali was fined £600, and ordered to pay a £15 victim's surcharge as well as £43 prosecution costs. His licence was endorsed with six penalty points.
"Mr Loophole" became involved when Ali was summoned back to court after a second information was laid regarding the speeding incident. Mr Freeman acted as Ali's advocate at the second trial, which was held at Horsham, West Sussex. Cross-examination of a police witness revealed errors in police statements, and Ali was acquitted on the second information after the prosecution offered no further evidence.
Immediately after the acquittal, Mr Freeman applied to the court to set aside Ali's earlier conviction at the first trial on the grounds that - despite Ali admitting the speeding offence - the conviction was also flawed by errors and inaccuracies in police statements.
The case came to London's High Court this week because the magistrates' court refused the set-aside application last November, saying Ali had not been misled and had suffered no injustice after admitting excess speeding.
Dean George, representing Ali at the High Court, argued that the magistrates' refusal was "wrong and unreasonable". But Sir John suggested to Mr George that Mr Freeman should have put all his cards on the table and told the second trial at the outset about Ali's earlier conviction - and that he intended to apply to have it set aside.
That, said the judge, would have enabled the case to be reopened and further evidence called, including a DVD corroborating that a speeding offence had been committed.
Later, Mr Freeman said in a statement: "Whilst I fully respect the comments of the High Court in relation to this case I maintain that clients demand and expect that their lawyer will fight robustly on their behalf. That is what I do and will continue to do within the legal boundaries."