M1 suspicious object thought to be 'highly corrosive' hydrochloric acid

The suspicious object that led to part of the M1 being closed for several hours is believed to be hydrochloric acid, police have said.

Officers have appealed for information as they try to work out why the "highly corrosive substance" might have been left under a bridge on one of Britain's busiest roads.

Thousands of motorists were trapped on the motorway for around 12 hours after emergency services were called at 7.30am on Tuesday.

Pictures on Twitter showed people playing football and other sports on the clear side of the carriageway as their cars were stationary for so long.

The substance was found in a 5 litre container in a black refuse bag on the hard shoulder, underneath a road connecting the villages of Little Linford and Gayhurst, near Newport Pagnell, Buckinghamshire.

The bomb squad was called and a robot dispatched to examine what appeared to be a sack or bag containing the substance.

Inspector Scott Long of Thames Valley Police said: "We are appealing to anyone who knows why or how this object was left under a bridge about two miles past the Newport Pagnell services on the southbound carriageway of the M1.

"The object has now been removed from the scene in a secure container but is still being analysed - however, we do know the substance is a highly corrosive material, possibly hydrochloric acid."

He said the substance had reacted with something else, causing it to discharge on to lane one and lane two of the southbound carriageway.

"We are keeping an open mind as to how the object was left at the scene but at this stage we are investigating the incident as an offence under Section 23A of the Road Traffic Act, which is placing an item on a highway or carriageway with intent to cause danger to other road users."

Inspector Long said there was no evidence to suggest it was a terror-related incident.

"We apologise for the inconvenience caused to motorists who were stuck in queues yesterday but your safety, and the safety of our officers and the staff of our partner agencies, Is our priority," he added.

Anyone with information about the incident, including motorists who may have dashcam footage of the object being left at the scene, are asked to contact Thames Valley Police by calling 101 and quoting reference 138 (19/9).