Police cordoned off roads near the Government chemist’s laboratories for more than an hour following a security alert.

Officers, a specialist dog unit and ambulances descended on Queen’s Road, Teddington, last night.

Police assessed an object on a road next to LGC laboratories - which is the host organisation for the Government’s chemist Dr Derek Craston and provides expert advice on the implications of policies, standards and regulations – before concluding it was not dangerous.

A police spokeswoman said: “Safety precautions, cordons and road closures were put in place. The road closures were lifted at 8.30pm.”

The National Physical Laboratory Sports Club said its members were unable to get in or out until about 9.30pm.

Martin Wicks, chairman of the NPL Sports Club, said: “We had some people turn up from Teddington Rugby Club who hadn’t been able to get out the gate.

“We stayed here until the police said it was all clear. They didn’t say anything about what was going on.”

Neighbours took to Twitter to warn others about the unfolding drama and traffic disruption.

Teddington_Town wrote: “[Breaking] something quite major happening in NPL / LGC grounds. Half a dozen police cars, ambulance, and dog unit. Area cordoned off.”