Residents in Lennoxtown last night said they were shocked by the tragedy, and said a number of rumours had swept through the village about what had happened.

One member of staff at Campsie Golf Club said: “We’ve heard so many things to be honest, all different stories. It happened about a mile from here but there’s no one we know of with children that age in this area.”

Local resident Brian Scott added: “People are distraught. Actually something like this happened not all that long ago in this area.”

At the Drookit Dug pub on Main Street, bar staff said customers were horrified at what had happened. One woman, who refused to be named, said: “Everyone is talking about it and we’re beginning to hear the same stories over and over about what happened.”

The car was discovered on Crow Road, the B822, around one mile outside Lennoxtown in the shadow of the Campsie Fells in East Dunbartonshire. It was found in a layby leading to a forestry track close to the border separating the jurisdictions of Strathclyde Police and Central Scotland Police and both forces were at the scene last night.

The B822 is a rural country road linking Fintry and Lennoxtown. Last night a road block, covering eight miles of the road, had been placed outside Campsie Golf Club, near the scene of the tragedy with motorists turned away.

A female police officer would only tell drivers there had been “an incident” and that the road would be closed for the “forseeable future”.

Police last night refused to divulge any details on what had happened. Inspector Jan Connolly would only say: “Police are investigating the suspicious death of two children aged two and six- years-old.

“They were found this evening within a parked car. Police are following a positive line of inquiry.”