FORENSIC officers were spotted combing a building busy city centre street this morning. 

An officer for the Department for Science and Technology Laboratories (DSTL) - a UK Government department - dressed in a white boiler suit was seen inspecting part of the building at Buchanan Subway station. 

He was accompanied by at least two cops. 

A spokesman for Police Scotland said: "Officers were assisting an external agency with an annual survey."

The study was being carried out by investigators from the Department for Science and Technology Laboratories (DSTL), part of the UK Government's defence and security operations. 

It was a "routine investigation" to test the levels of traces of explosives in the environment. 

It is important to know the levels of explosives in the environment normally, explained the DSTL, because it can help with criminal investigations and interpreting evidence. 

Investigators wear distinctive white suits to stop their samples from being contaminated, the Department said. 

An information leaflet sent by the Department read: "Scientists from the DSTL are conducting a routine survey to detect and identify traces of explosives present in the general environment.

"There is no need to be concerned, these types of survey are routine and this work is not related to any specific threat or any Covid-19 concerns.

"Numerous locations and are being sampled, particularly transport, retail and leisure hubs.

"Personnel undertaking the survey are wearing protective clothing to ensure they do not contaminate the particular areas being sampled and we get a true picture of any background contamination.

"The sampling techniques used are non-invasive, non-toxic and leave no residue.

"The data is used to understand the level of explosive traces in our environment and can be used to interpret evidence gathered at potential crime scenes to aid the criminal justice system and maintain the security of the UK.