TESCO have revealed the cause of the thick smoke that filled their Dunfermline Duloch store on Tuesday afternoon. 

A video posted to social media showed a substantial amount of smoke in the shop, with customers apparently going about their shopping as normal. 

However, Scottish Fire and Rescue had no record of the incident.

Now, the supermarket has explained what happened. 

It has been revealed that the smoke was not a fire but rather a security system which was deployed by accident.

A spokesperson for Tesco said: "There was an accidental triggering of an internal security system earlier today – although the smoke cleared in a matter of minutes, the store didn’t need to be fully evacuated and remains open as normal."

Customers entering the store were asked to hold off for a few minutes to allow for the smoke to clear. 

Tesco went on to apologise for the inconvenience.