Prison security guard Muhammad Ikhlaq picked up the known sex worker on Wednesbury Road, in Walsall's red light district on May 7, a court heard yesterday.
The 39-year-old, of New Road, Dudley, who is married with four children, was driving along Wallows Lane with the woman in the passenger seat of his black Nissan Micra when officers stopped and arrested him.
He told them he had needed to buy tomatoes to bring to a colleague at work the next day.
He claimed he asked the woman for directions to the nearest grocers and she offered to show him the way.
Two plain-clothed police officers followed the pair in an unmarked car.
They had been working on Operation Scarlet & Minus, a crackdown on kerb crawlers in the town's worst-affected areas.
The officers stopped Ikhlaq at traffic lights on Wallows Lane and arrested him on the spot, before taking him to Bloxwich Police Station for questioning.
Ikhlaq denied an offence of soliciting for the purpose of obtaining sexual services in a public place. "I asked her because I thought she looked local and I was in a hurry. "She said she was going that way,"he said.
Magistrates said Iklaq's story was 'not credible' and ordered him to pay a £400 fine, £625 costs and a £40 victim surcharge.
Speaking after the hearing, PC Stacey Paterson said: "I've heard some excuses before but in the 10 years that I have been a police officer I have never heard a kerb crawler covering up his crimes by claiming to be buying tomatoes."