Thames Water's Swindon office on Kembrey Business Park was placed into full lockdown this morning, after a suspicious white substance was sent to the company in the post.

Staff were locked down inside the building for several hours on Tuesday, October 17, as over 10 emergency vehicles attended the scene, including the police, ambulance and fire service.

Experts wearing white protective suits and gas masks were seen entering the building to investigate the suspicious substance.

LIVE UPDATES: Thame Water offices evacuated

However, Wiltshire Police have confirmed in their latest statement that the substance was not harmful: "We were called to Thames Water, Kembrey Business Park, Swindon around 8.30am this morning (Tuesday) after reports of a suspicious package that had been sent in the post.

"The package contained an unknown white powder.

"The building was put on lock-down as a precaution, and staff were supported throughout the morning.

"The package was deemed not to be harmful, and the scene has been lifted."

An anonymous employee of Thames Water who was trapped inside the building has told The Adver that the white substance was in fact 'concrete powder', however Swindon Police have not commented on the substance expect to say that it is not a cause for concern.