Police are scratching their heads over strange symbols that have appeared in some streets in Uxbridge.

Chief Inspector Rob Wilson of Hillingdon police confirmed they were not the type of mark used by burglars to identifiy areas or properties that could be worth breaking into - but confessed beyond that, he was baffled.

We thought it would be done by a utility company and our intelligence unit is looking into it to see if someone is using that,” he said.

“It could just be graffiti, someone using a template.

“We are keeping an open mind and any information would be gratefully received.”

One theory suggested is the symbol is the location point for a surveyor’s theodolite. However, most theodolites are mounted on tripods not a single leg.

One of the symbols appeared in the pedestrianised section of Uxbridge High Street, close to Boots, and another has been seen in Grove Road.