Lord Archer's former secretary told the Old Bailey yesterday that she often bought expensive gifts for him to give to his mistress and girlfriends.
Mrs Angela Peppiatt (56) was being questioned about her credit-card account during the three years she worked for the novelist.
She said she was sent by him to Harrods, Burlington Arcade and jewellers Aspreys to buy presents using her card. She reimbursed her Access account to the tune of £2,531 by June 1987, using blank cheques from Lord Archer's personal account.
But she said this was with his knowledge and was part of the "expenses culture" of the time.
The court has been told that Lord Archer resigned as deputy chairman of the Conservative Party in October 1986, after allegations that he had associated with a prostitute.
Mrs Peppiatt pointed to one entry in her card statement for November 1986 and said it was typical of items which she thought Lord Archer would not like "to come out in court".
She said: "It was possibly a Gucci item. I think that was one of the items I was asked to get, and I cannot remember what it was. It was the type of gift I would have been asked to buy for Andy. Andy was Jeffrey's mistress at the time."
Asked by Mr Nicholas Purnell QC, defending, if she meant Ms Andy Colquhoun, she replied: "Yes."
Asked about items on her credit statement, she said: "I certainly do not think Jeffrey will be very happy about this. It is something I have not talked about before, items I have bought on his behalf, and I have documentation." The court has been told that Ms Colquhoun was Mrs Peppiatt's predecessor, and remained a frequent visitor to Lord Archer's penthouse apartment in central London.
Lord Archer (61) denies four charges of perverting the course of justice, two of perjury and one of using a false instrument in relation to his successful 1987 libel case against the Daily Star which said he had had sex with the prostitute.
Mrs Peppiatt has told the court that Lord Archer asked her to take part in the "deception" by filling out a blank diary for the relevant time in September 1986.
Mr Ted Francis (67), a television producer from Surrey, denies perverting the course of justice by providing Lord Archer with a false alibi which was never used in court because it was for the wrong night.
The court has been told that when in 1999 Lord Archer was confronted with the false alibi, he said he had acted to protect a woman with whom he had been having dinner.
Mr David Waters QC, prosecuting, told the court Lord Archer was willing to allow newspapers to believe that the woman was Ms Colquhoun.
But Ms Colquhoun, who is now Mrs Robert Waddington, was in Greece at the time.
Mr Waters said she had "remained a close friend of Jeffrey Archer's" after relinquishing her position.
Mrs Peppiatt had earlier denied "fiddling her expenses", but admitted that she had charged for some personal items, including a family holiday in Greece.
The hearing was adjourned until today.