The vandalism is said to have happened between 10pm on Friday, July 25 and 5pm the next day.

Now police are asking for the public’s help. A white Vauxhall Astra and a black Volkswagen Golf, parked on O’Hare, sustained scratch damage to their nearside and offside respectively on the Friday.

Then between 3.15pm and 3.30pm on the Saturday a black Vauxhall Zafira and a grey Renault Scenic were scratched along their nearside.

Inspector Neil Smith said: “The motivation behind these incidents isn’t clear as yet but the owner of each car is likely to face a substantial repair bill.

“At least two of the incidents occurred on Saturday afternoon and I’m confident that someone in the community either witnessed these crimes being committed or has knowledge of them. “I would ask that anyone with information either contacts Dumbarton Police Office on 101 or, if they prefer, makes an anonymous report to Crimestoppers on 0800 555 111.”