M1 closed in both directions as bomb disposal unit investigates 'suspicious object' found under motorway bridge

The M1 motorway was closed for several hours in both directions on Tuesday due to reports of a "suspicious object", which was later discovered to contain a highly corrosive material.

Thames Valley Police are investigating what the substance was, which had spilled across two lanes of the road.

Diversions were in place between between junction 14 for Milton Keynes and junction 15 for Northampton for around nine hours.

The suspicious object was found beneath one of the motorway bridges around 7.30am, Thames Valley Police said.

A bomb disposal unit was seen travelling along the hard shoulder towards the scene, although the police force later said there was no evidence that the incident was terror related.

Three fire crews from Buckinghamshire Fire and Rescue Service attended the scene.

Highways England warned of "long delays" on approach to the area.

It said to expect delays of at least an hour and recommended motorists use alternative routes.

Photos shared on social media showed people walking along the hard shoulder with their suitcases.

One user reported hearing a bang. They added: "Suspicious package dealt with maybe?"

The northbound carriageway was reopened shortly after 5pm, but the road remained closed southbound at junction 15.

Chief Inspector Mark Lewis of the Joint Roads Policing Unit for Thames Valley and Hampshire said: "There is no evidence to suggest that this is a terrorist related incident.

"The object does not contain an improvised explosive device and therefore has been no controlled explosion [sic].

"However, the object contains a highly corrosive material which has leaked across lanes one and two, therefore the clear up process will take a significant amount of time.

"Chemical analysis is ongoing to ascertain what the substance within the object is".