Police stopped traffic on the M4 at Swindon after responding to reports of a pedestrian “acting suspiciously.”

The motorway was blocked heading westbound between junctions 15 and 14 after police were called to the turn-off to Swindon, at around 8.20pm on Saturday night.

Traffic was held for over an hour while police investigated, causing two miles of congestion and delays of up to half an hour for motorists.

Police have now confirmed the closure was due to reports of a male pedestrian acting suspiciously at the side the road, near junction 15.

Officers at the scene were unable to locate the man, however, and the force say their enquiries are ongoing.

A spokesperson for Wiltshire Police said: “We responded to reports of a male pedestrian acting suspiciously beside the M4 near Junction 15 at about 8.20pm last night.

“On attendance, officers were unable to find the reported person. Our enquiries are ongoing.”

The road reopened fully at around 9.30pm.

At the time a National Highways spokesperson said: “The Wiltshire Police led incident on the M4 westbound between junctions 14 and 15 has been safely resolved.

“The traffic has been released, with all lanes open.”