Terence McLernon had been reported to police in connection with two separate incidents which took place four months apart, outside Knightswood Secondary and Clydebank High schools.

On both occasions McLernon, of Carlibar Avenue in Knightswood, was spotted in the Vauxhall Zafira carrying out the lewd acts.

The 27-year-old works as a table tennis coach at kids’ breakfast, lunch and after school clubs.

Witnesses during the trial at Dumbarton Sheriff Court included a 52-year-old woman who was dropping her daughter at Knightswood Secondary on the morning of November 20 last year.

She told the court that she had parked behind a silver car in Knightswood Road when she saw a man sitting in the driver seat acting suspiciously and looking around him.

The court heard that the street was busy with school kids as the bell was about to ring. In evidence she said that the driver seemed to be watching the children and it looked as if he was moving his body back and forward.

The woman decided to get out of her car to investigate and as she walked past the silver car she glanced in the window and saw what she described as a “bulge covered by burgundy boxer shorts”. She then turned and walked back but by then McLernon had cupped his two hands over his groin area.

Alarmed by what she had saw she contacted the campus policeman at the school.

A witness to the second incident described how he was upstairs at his home tidying his daughter’s bedroom, in Janneta Street opposite Clydebank High on March 28 this year, when he noticed a car sitting in the street outside.

The 44-year-old father told the court that he could see the driver of the vehicle looking around and thought he was trying to see the house numbers.

He then noticed the drivers hands were at his groin area and that he was performing a sex act on himself.

When he realised what was happening he went downstairs phoned the police, took a picture of the car parked outside and noted the registration number of the car.

McLernon took the witness stand and under cross examination claimed, that on the occasion outside Knightswood Secondary where he had previously worked, that his body movements could be explained by the fact that he was cleaning the inside of his car and the dashboard with a baby wipe.

The only explanation he could offer for what he was doing during the incident in March in Clydebank was that he was breaking a bread roll he was having for his lunch and the witness must have been mistaken in what he saw.

Finding McLernon guilty on both charges, Sheriff Mhari McTaggart said: “I have to say that the two Crown witnesses were amongst the most credible witnesses I’ve heard in a long time. They have no axe to grind with you.” Sentence was deferred until September 9 to allow for a criminal justice social work report and a risk assessment to be carried out.

McLernon was granted bail placed on the sex offenders register.