Lord Archer was himself the subject of a Department of Trade and Industry investigation into dealings in Anglia shares before its takeover by MAI.
Karen Morgan Thomas, a former employee of James Capel, the stockbroker, also denied she attempted to prevent the Guardian from publishing details of her share transactions by a court injunction.
It emerged, however, that Ms Morgan Thomas has close links with the Conservative Party. In a press statement, she said: "I utterly refute any suggestion that I was acting on the basis of insider information from Lord Archer or any body else."
Ms Morgan Thomas, 41, who read her statement at her solicitor's office, was distressed. She said after the Guardian story, it had become "quite impossible for me to live my life".
She claims she went to the courts on Wednesday to force the Guardian editor, Peter Preston, to swear an affidavit that it could justify its story in the event of a libel action. Frank Presland, her solicitor, refused to be drawn on whether she would proceed with an action.He did say that his client "had strong links with the Conservative Party".
Mr Preston said yesterday that he was standing by his newspaper's story.
Ms Morgan Thomas said she had bought shares in Anglia on 4 January 1994 after a Sunday Times tip that it was one of several television companies which were possible candidates for a takeover bid. On 16 January 1994, the MAI bid was announced, causing thecompany share price to go from 180p to 664p. Ms Morgan Thomas made, according to the Guardian, more than £20,000 profit.
Ms Morgan Thomas said she complied with her employer's in-house rules by reporting her dealings to her bosses.
Labour repeated its demands for the Department of Trade and Industry to publish all the available evidence on the Anglia share dealings. Brian Wilson, the party's trade and industry spokesman, said: "There are many highly unsatisfactory and politically tainted aspects of this affair which will not go away until Mr [Michael] Heseltine allows full light to be shed on all the available evidence."
James Capel refused to comment, saying: "The transaction was made through the broker's personal account and, therefore, we have not launched an investigation."
At the Stock Exchange, a spokesman refused to confirm that it was investigating.