In his opening speech for the prosecution at Southwark Crown Court yesterday, Philip Katz, QC, representing the Department of Trade and Industry, said Mr Hipwell had made about £41,000 between August 1999 and February 2000 by buying and selling the shares of companies which featured in his column.
Mr Katz said Mr Hipwell's co-columnist on the Mirror's City Slickers column, Anil Bhoyrul, pocketed about £15,000 in the same fashion, while Terry Shepherd, a former day-trader who was in close contact with the two journalists, made a profit of about £17,000 during the same period.
Mr Hipwell and Mr Shepherd are accused of creating a misleading impression of the value of investments through the use of the Daily Mirror's City Slickers column. Mr Bhoyrul is not part of the trial. The defendants both deny charges of manipulating the market.
Mr Katz accused Mr Hipwell of writing stories, on more than one occasion, simply to "ramp" the value of shares in a particular company "quite irrespective of the accuracy ... of the story".
He told the jury that the pattern of "purchase, tip and sale" of shares inferred there "was an agreement to use the City Slickers column to ramp the price of the shares and ... therefore to manipulate the market", adding that some stories behind the tips were "untrue, inaccurate or otherwise fairly misleading".
"The intentional failure by them to disclose what they were really doing is, as far as [Mr Hipwell is] concerned, the most serious aspect of this case," he said.
Mr Katz highlighted the example of a healthcare company called Oxford GlycoSciences in which the two journalists and Mr Shepherd all bought shares the day before the Mirror published a story claiming the company was close to creating an Aids vaccine.
He added that on the afternoon before the story appeared, Mr Hipwell, using the pseudonym William Corlyon, put out a message on the bulletin board of a private investor website, www.iii.co.uk, encouraging investors to buy the stock.
Under the heading of "City Slickers - urgent news", his message read: "Strong rumours that the boys from the Mirror are working on a big story re: Oxford GlycoSciences - something about developing an Aids vaccine - so could be profitable to pile in big time." Mr Katz said "Mr Corlyon" and Mr Shepherd communicated through the iii bulletin boards, but said it was unclear whether Mr Shepherd was aware of Corlyon's true identity. As well as using an alias, Mr Hipwell's username for the website was "Twatface", he said.
The three sold their holdings in the healthcare company several days later, after the story had appeared.
Mr Katz said one of his key witnesses would be a representative of Oxford GlycoSciences, who would testify there was "no truth" in the Mirror's story. Mr Katz admitted, however, that on this occasion, the defendants lost money on their investment.
Mr Katz also highlighted a transaction relating to Leeds Sporting - the holding company of Leeds United football club - which was mentioned several times in the column in August 1999. Having both bought shares in the company at about 25p each on 10 August 1999, the two journalists wrote a story a week later suggesting that the broadcaster BSkyB was about to offer 45p a share to take a near 10 per cent stake in the group. "That should push the price up big time," the column said. "Get in very quickly or you'll miss the bonanza."
The pair sold their shares on the day as the story was published. A deal with BSkyB never materialised.
Mr Katz said that while the column was deliberately written in a brash confident tone, he claimed it went "beyond tabloid hype" in many cases.
"They knew perfectly well that those predictions were not just hype but were unrealistic ... and contributed to a misleading impression of the value of the shares," he told the court.
The case continues.