Requests from Lord Archer for alibis to cover up extra-marital activities from his wife were "not out of the ordinary", the Old Bailey was told yesterday.
Lord Archer had many infidelities, including one which took place in Nigeria, and the best-selling author's friend, Mr Ted Francis, thought one of the flings had "landed him in trouble" with Lady Archer when he gave him a false alibi 14 years ago, the jury was told.
But after Lord Archer's high-profile libel trial in July 1987, Mr Francis realised the alibi had been intended for use in the action, it was alleged.
Lord Archer and Mr Francis face dishonesty charges after the News of the World revealed in November 1999 that Francis had been asked before the trial to provide a false alibi for September 9th, 1986. The alibi was never used because the Daily Star, which had alleged the then deputy chairman of the Conservative Party had sex with a prostitute, realised the day in question was the day before.
Lord Archer (61), won £500,000 damages, which he said he would give to charity.
Lord Archer, who has homes in Cambridge and central London, denies four counts of perverting the course of justice, two counts of perjury and one of using a diary as a false instrument.
Mr Francis (67), of Cranleigh, Surrey, a television producer, denies one charge of perverting the course of justice.
News of the World reporter Neville Thurlbeck told the court Francis had thought long and hard before agreeing to have telephone conversations with Lord Archer taped by the newspaper.
He said: "Ted Francis told me that he was providing a false alibi for Lord Archer because he was requested to do so to cover up an extra-marital indiscretion.
"He explained to me that during the course of the friendship between Lord Archer and Ted Francis, he knew of previous marital infidelities.
"He cited many infidelities, one of which took place in Nigeria, and cited that such a request was not out of the ordinary. One of the marital indiscretions had landed him [Archer] in trouble with his wife.
"It became obvious to him that the alibi was in connection with the libel trial, but only subsequent to the libel trial.
"Mr Francis only realised that he had provided an alibi for the libel trial and not for the marital indiscretion after the libel trial had actually taken place.
"Up until that point, he was very firmly of the belief that he was providing an alibi for a marital indiscretion."
The publicist Mr Max Clifford told the court last week that Mr Francis approached him about the story because he did not want Lord Archer to be Mayor of London.
Archer stood down as Conservative candidate after the News of the World story was published.