An antique clock spilling mercury was the cause of a major health scare today which caused the evacuation of some residents and for a 75 metre exclusion cordon to be put in place.

Fire crews from Ely, St Neots and Sawtry were called to the incident on Downham Road, Ely, just before 10.30am.

“We found a spillage of mercury from an antique clock,” said a fire service spokesman.

And so began an operation that caused disruption to residents and traffic for much of the day – and for others to shut their windows and lock their doors.

Station Commander Jamie Johnson, the officer in charge at the scene, said: “Due to the hazardous nature of mercury we had to ensure it was contained quickly and safely. “The crews did a great job initially by containing the substance to the premises and preventing it from spreading.

“A cordon was put in place to ensure the crews could carry out the necessary actions safely.

“This involved evacuating the buildings in close proximity to the source of the spillage, as well as closing some of the roads leading to the area. This was essential to ensure the situation could be resolved as quickly and safely as possible.

“We want to thank all the local residents and business for their patience during the incident.

“We appreciate the cordon was in place for most of the day but this was necessary to ensure the crew could safely contain and collect the mercury for it to be disposed of. “We apologise for any inconvenience caused.”

The 75 metre cordon was put in place affecting Downham Road, West Fen Lane and Chapel Street.

Cambs Fire & Rescue Service said on their Facebook page: “This is a precautionary measure and only the premises within the cordon have been evacuated.

“Other premises need not take any further action.

“Residents are asked to avoid the area if they are on foot on in a vehicle.”

The advice came after a warning for people in the city to stay indoors with their windows locked and doors closed until further notice.

Schools in the city were also on lock down earlier today with no children being allowed in or out.

Cambridgeshire Constabulary said: “The advice to stay clear of the area has been given as a precaution to ensure the crews are able to stop the potential spread of mercury and clear the spillage as safely as possible.

“The premises are also located on a blind corner with heavy traffic flow, meaning it would have presented additional challenges for the crews, so the area closed off.”