Her co-stars were her fiance, Geoff Knights, a businessman who is not thought to possess an Equity card, and two feature writers from the Sun newspaper.
Miss Taylforth, 37, who plays Kathy Beale in the television soap opera, was aiming to demonstrate that she had not been having oral sex with Mr Knights in the Range Rover, when a police officer, Constable Terry Talbot, pulled up and told them: 'I'll have you for gross indecency.'
She is suing the Sun for libel over an article which claimed that she was indulging in a 'sex romp' with her fiance after stopping on a slip road of the A1.
Miss Taylforth says that Mr Knights suffers from pancreatitis, a condition brought on by drinking too much for too long, and had become ill after consuming a considerable amount of champagne at the Royal Ascot race meeting.
As she drove him home, he told her that he was going to be sick and she pulled on to the slip road near Borehamwood, Hertfordshire. To ease the pressure on his stomach, she undid his belt and pulled his trouser zip down.
PC Talbot saw her leaning over her fiance with his trousers undone and reached entirely the wrong conclusion, she says.
In fact, Michael Beloff, her counsel, told the court, she was comforting him by rubbing his stomach. Yesterday, as showers scudded across the precincts of the High Court, Miss Taylforth and Mr Knights staged a re-enactment of the incident, watched by Mr Justice Drake, several leading barristers, the jury and journalists.
Looking distinctly unamused, the couple clambered into their blue Range Rover and restaged Miss Taylforth's version of events as the eight men and four women on the jury peered through the windows of the vehicle.
After they had finished, two feature writers from the Sun took up what the newspaper claims were the couple's real positions.
As the woman almost buried her head in the man's lap, the jury once again circled the car and PC Talbot looked on. The pair from the Sun emerged flushed and chuckling from their performance, and the court adjourned for a much needed break.
The case continues.
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