A St Albans police community support officer accused of performing a sex act while behind the wheel as he watched a teenage girl has been convicted of outraging public decency.

Ex-soldier Kelvin Mackenzie, 49, of Holbeach, Lincolnshire, denied committing an act which outraged public decency, claiming it simply was not him, or his car.

But yesterday (Wednesday), a jury of eight men and four women at Chelmsford Crown Court did not believe the suspended PCSO, and took just over an hour to reach their guilty verdict.

Judge Christopher Morgan indicated Mackenzie would not be going to prison, and adjourned sentence for reports until the week of February 22. He was released on bail.

Prosecutor Alex Rooke, opening the trial at Chelmsford, said cyclist Adam Barnes saw a middle-aged man engaged in a sex act on himself behind the wheel of a red Renault Megane about 4.50pm on July 30, 2014.

Mackenzie, a full-time PCSO since 2005, was based in St Albans at the time of the incident.

He was on his way home from the city’s station to Holbeach when the cyclist saw through an open passenger window what the motorist was doing as he drove slowly along Faircross Way in St Albans, the jury was told on Tuesday (26).

Mr Barnes, who grew up in Faircross Way and was visiting his father’s house to go on a bike ride together, told the court he was “a bit shocked” by what he witnessed.

He said: “When he drew level I could see that he was struggling. I assumed he was trying to put his seat belt in but as I looked in the window I could see what he was doing.

“He was looking straight ahead. There was a girl walking along on my side of the pavement, about 16-17.”

The prosecutor said the driver appeared to be ‘fixed’ on the girl.

Giving evidence, Mackenzie said his car was not in Faircross Way at any stage on that day, adding, “I didn’t commit this offence”.

He had finished his shift at St Albans police station at 4.30pm, and was leaving the city for his two-hour journey home. Mackenzie’s route took him close to Faircross Way but he did not drive down it. He had moved to Holbeach in November 2012.

He suggested that the witness had made a mistake in the registration number he wrote down, that the number might be very similar to his, or cloned.

Mackenzie, who served in the Royal Anglian Regiment, including in Northern Ireland in his early 20s, is of previous good character.

He had arranged a transfer to Cambridgeshire as a PCSO to be closer to his new home when the allegation was made, and he was suspended.