But his deception was unearthed when he left his own phone number to call back. 

Yesterday Leathley, who practices in Wales, ended up on the wrong side of the legal system when a High Court judge criticised his ?discreditable? conduct. 

Mr Leathley had been fighting against disciplinary proceedings after accusations that he been rude to a court clerk when he came up with the trick. 

The ?victim? had said that she was too ill to give evidence in the hearing but Leathley was convinced that she was lying - and was still at work. 

In order to find out he impersonated the voice of top QC Joel Bennathan, who was investigating the case for the Bar Standards Board, when he called the courts and demanded to speak to her in June 2007. 

When he was told she was not immediately available he left his own phone number -- which was recognised by the office. 

In November 2008, a bar disciplinary tribunal found that Mr Leathley had ?intentionally claimed to be Mr Joel Bennathan QC?. 

After finding that Mr Leathley had ?attempted to deceive the recipient of the telephone call?, the tribunal fined him £1,000 and ordered him to pay costs of £2,876. 

Mr Leathley has fought to overturn that ruling ever since but has now finally had his appeal dismissed by Mr Justice Burnett. 

Yesterday he insisted he had done nothing unacceptable, explaining that criminal lawyers ?develop a nose? for such things. 

Mr Leathley said what he did was ?an acceptable tactic? as he ?suspected a lack of frankness? on the part of a court official who had accused him ?essentially of rudeness?. 

The judge rejected Leathley?s plea that the tribunal was ?infected? with apparent bias as its lay members of the panel had their expenses and fees paid by the Bar Standards Board, which is also the prosecuting authority in bar disciplinary matters. 

Mr Justice Burnett also rejected Leathley?s plea that impersonating Mr Bennathan was an acceptable ?ruse de guerre? he used as a private citizen to defend himself against a claim which, he believed, had been ?blown out of proportion?. 

Ruling that there was ?no merit? in Leathley?s appeal, the judge concluded: ?We do not believe that the question whether the conduct was discreditable involves a fine moral judgment. 

?We conclude that ?discreditable? is an apt word to describe what the petitioner (Mr Leathley) did and agree with the conclusion of the tribunal to that effect. 

?In the result, this appeal is dismissed?.