Before being involved in a crash that killed two people on the M25, a van was seen driving on the wrong side of the motorway, police say.

The incident took place just before 4am on Sunday, February 4, when Hertfordshire Police officers spotted a white Citroen Dispatch on the M1, which had been reported as stolen.

A short time afterwards, the officers activated their vehicle’s lights and sirens in an attempt to stop the driver of the van. 

Echo: Two police pursuits preceded the crash.Two police pursuits preceded the crash. (Image: UKNIP)

After the vehicle failed to stop, a pursuit was initiated, but was later called off due to the risk of a collision being too high.

Shortly before 4am, on Breakspear Way, a second pursuit took place which was also abandoned.

A short time later, the van was then seen by a police officer travelling on the wrong side of the M25.

Echo: A man and a woman have been confirmed dead following the crash.A man and a woman have been confirmed dead following the crash. (Image: UKNIP)

The officer followed the van on the correct side of the road but did not activate the vehicle’s lights or sirens.

At approximately 4.08am, the van was involved in a crash with three other vehicles on the M25 between junctions 21a and 22 (Watford and St Albans). 

A woman, from Canvey, died as a result of the crash on Sunday, with the driver of the van taken to hospital where he remains in a serious condition, according to the IOPC (Independent Office for Police Conduct). A man in another vehicle was pronounced dead on Monday.

Hertfordshire Police confirmed that a man in his 20s was arrested on suspicion of causing death by dangerous driving.

A criminal investigation into the fatal crash is also being carried out by Essex Police.

IOPC investigators have since been sent to the scene to gather information, with their investigation "in the very early stages".

IOPC regional director Charmaine Arbouin said: “Our thoughts are with all those affected by this tragic incident.

"Given that police officers were pursuing one of the vehicles before the fatal collision, it’s important that we independently investigate the actions and decision-making of the officers involved. 

“We will ensure that our enquiries do not impede the police investigation, and we will keep those involved regularly updated.”