The accusation came as Guy Snowden, an American businessman, sought a re-trial after a libel jury found that he had attempted to bribe Virgin founder Richard Branson.
Mr Snowden was ordered to pay pounds 100,000 and had to resign from the board of Camelot, the company which runs the National Lottery, after the case last year which left his reputation in tatters.
Yesterday Gordon Pollock QC, representing Mr Snowden in the Court of Appeal, claimed that Mr Carman, who represented Mr Branson, had broken the rules of cross-examination and prejudiced the jury so his client could not get a fair trial.
The member of the Camelot consortium had accused the Virgin boss of libel after he told BBC's Panorama programme that he had been offered a bribe to withdraw his rival bid to run the UK lottery.
Mr Branson had counter-sued both the company, GTech, and Mr Snowden, its chairman, for publicly denying these allegations. The jury found in his favour after a lengthy High Court trial last year.
Mr Pollock accused Mr Carmen of "improper use of documents". He said Mr Carman produced a letter between two Camelot directors - an inadmissible document - which Mr Snowden's original counsel Richard Ferguson QC had been forced to object to.
"They were designed to create in the jury's mind the idea that there were documents of some weight which contradicted Mr Snowden's evidence," said Mr Pollock, adding: "In a word that is dirty pool and it is not supposed to happen in front of the jury."
The Virgin director had told the court that during a meeting at his home in Holland Park, west London, in 1993 Mr Snowden said: "I don't know how to phrase this, Richard. There's always a bottom line. I'll get to the point. In what way can we help you? I mean, what can I do for you personally?"
G Tech, which was forced to pull out of the Camelot consortium after the libel case, is not appealing against the 1998 decision.
The case continues.