Scotland’s national clinical director has outlined a key “risk” factor that could be causing the spread of coronavirus.

Professor Jason Leitch said that people sharing cars could be causing cases of coronavirus to remain high in parts of the country.

The lack of ventilation and also people often not wearing masks can make the situation a driver of spreading the disease.

Current Scottish Government guidance is that people should only travel in cars “with members of your own, or extended, household.”

That advice is relevant for all areas in Scotland, regardless of lockdown tier.

Glasgow Times: National Clinical Director Jason LeitchNational Clinical Director Jason Leitch

But Professor Leitch said during Test and Protect interviews, car sharing “comes up quite a lot”, according to the Scottish Sun.

It comes as St Mirren were found to have breached coronavirus protocols after officials admitted some players were car sharing.

Professor Leitch said: "We have asked people not to car share unless they absolutely have to across the whole of society. 

"When we do the Test and Protect interviews with positive cases you can't know for sure where people got the virus because the incubation period is too long.”

Glasgow Times: The Scottish Government is advising against car sharingThe Scottish Government is advising against car sharing

He added: "Car sharing comes up quite a lot.

“It makes sense because you are in an enclosed space, often poorly ventilated and maybe not wearing a face covering. 

"So cars are a risk.

“We are asking people throughout society not to car share unless they have to." 

However, the national clinical director did outline some exemptions, such as needing to “take an elderly relative to a hospital appointment”

He added: "But you have to have a reasonable excuse to car share."