A POLICE headquarters is on fire this morning, after an overheated battery sparked an explosion.

Fire crews are currently battling the blaze at Durham Constabulary HQ, in Aykley Heads, Durham City.

A police spokesman said the fire, in offices, was started by a small explosion, believed to have been caused by a lithium battery overheating.

At midday four fire engines remained at the scene.

Around 20 firemen surveyed the damage but it appeared as though the blaze has been extinguished.