Detective Constable Dave O'Brien told the jury he found the morphine and diamorphine 11 months after the boxes in which the drugs were stored were recovered from a bedroom at Shipman's home.
Various medicines found in a C&A bag were handed to DC O'Brien, the exhibits officer, in September 1998.
Questioned by Ian Winter QC, for the defence, DC O'Brien said he found the drugs while he sorted out the exhibits to be returned or destroyed in August this year.
He said: "I entered it on the computer and I assumed what was written on the label was in the bag."
DC O'Brien agreed with Mr Winter that at the time he did not look in the packets and that the exhibits were not examined between 7 September 1998 and 26 August this year.
The jury was then told that the drugs had been recorded by Dr Shipman as being destroyed in 1995. Dr Shipman told police he had not kept drugs, nor had a register to do so, since 1976, according to a statement by DC Michael Beard, which was read to the court.
Dr Shipman, 53, of Mottram, Greater Manchester, denies murdering 15 female patients with injections of morphine, and forging the will of one of his alleged victims, Kathleen Grundy.
The jury heard transcripts of interviews with Dr Shipman by police after his arrest on 7 September last year. The trial continues today.Reuse content