Miss Slater, 26, will relive the trauma of her captivity when giving evidence against Michael Sams, 51, at Nottingham Crown Court.
Sams, of Barrel Hill Road, Sutton-on-Trent, has admitted kidnapping Miss Slater, falsely imprisoning her and demanding a pounds 175,000 ransom. He denies kidnapping and murdering Julie Dart, 19, in July 1991, twice demanding pounds 140,000 with menaces from Leeds City Police and demanding pounds 200,000 with menaces from British Rail. Yesterday, the jury listened to a tape recording of a telephone conversation in which a man's voice is heard giving instructions to Miss Slater's branch manager, Kevin Watts, on where to take the ransom money.
Detective Constable Susan Woolley told the court that it was the man she had spoken to from a call box on Crewe railway station in October 1991 as she followed the instructions of the BR blackmailer.
Earlier, the court heard that cash register till rolls recovered from Sams's workshop showed someone had interfered with the mechanism to change the recorded date of sales.
Neil Gibardi, an engineer, said that when he examined the register he found it was running a day late even though the correct time and date would have been programmed in by the manufacturer.
The jury has been told the blackmail letter to BR, which threatened to derail a train if the money was not paid, was posted in the Stoke-on-Trent area on 10 October 1991. The till roll purported to show two transactions at Sams's Newark workshop on that day but none for 9 October.
Mr Gibardi said that on another till roll covering part of February 1992, there were marks which indicated someone had twice altered the manufacturer's programme date.
Miss Slater, of Great Barr, Birmingham, was abducted on 22 January last year after meeting a man posing as a prospective house buyer.
She was released not far from her home after the ransom money had been left at an isolated bridge in South Yorkshire.
The trial continues today.Reuse content