The girlfriend of a firearms officer was put under pressure to lie about spiking his drinks by a senior policeman, a court has heard.

Metropolitan PC Michael Turner, 44, of Hawkes Road, Witham, is accused of conspiring with Nicola Howell, 49, to help him avoid punishment for a drink-driving offence.

The lawyer representing Howell accused Turner’s colleague, Inspector George Trebess, of pressurising her to claim she had spiked Turner’s drinks with vodka.

Both Turner and Howell, a senior nurse at Southend Hospital A&E, appeared at Chelmsford Crown Court accused of lying to Witham Magistrates Court when Turner faced charges of drink-driving.

Turner, a firearms officer with 20 years experience, had been at Howell’s home in Canewdon, near Rochford, in May 2010, when he decided to drive home in Witham following an argument.

After Howell called 999, police arrested Turner at his home later the same evening.

A breath test found he was two times over the drink-drive limit.

While waiting for the court case to begin, Mr Trebess, present as Turner’s senior officer, spoke to Howell, telling her she needed to be “truthful, consistent and get your facts in order” when she gave evidence.

Prosecutor David Holborn asked Mr Trebess in court: “Why were you poking your nose in something that was none of your business?”

Judge David Turner QC said: “There might have been the perception that you were heavying it up with her and paying no attention to the other witnesses.”

Turner, who could have lost his job if he had received a driving ban, was given a conditional discharge after magistrates accepted Howell’s story that she had spiked Turner’s lime and soda to help him relax.

But Howell later claimed she lied under duress because he had made threats to her.

Turner maintained the only alcohol he had knowingly drank on the day of his arrest was two pints of Guinness, but Mr Holborn, in his closing statement, urged the jury to reject the arguments of both defendants.

Expert witnesses had stated a pint of lime and soda would have had to have been at least a quarter full of vodka to explain the alcohol levels in Turner’s breath.

Mr Holborn said: “Mr Turner is lying to save his skin. How could he have missed the vodka? He simply cannot have failed to notice it.

“There was some unpleasant behaviour towards Ms Howell but not enough to make the defence of duress hold out.

“It may very well be she was the victim of the most unpleasant conduct from a man who has two sides to him, but she had every opportunity to avoid his threats.”

The jury is expected to retire to deliberate on Monday after hearing closing statements from defence lawyers and the judge’s summing up.

Turner and Howell both deny perverting the course of justice. The trial continues.