Three people were killed when a car towing a caravan crashed as it was being driven in the wrong direction on a busy motorway.
Thames Valley Police received reports of the Subaru Forester SUV being driven south on the northbound carriageway of the M40 shortly before 4pm on Monday.
A few minutes later it crashed into two other cars - a Ford Mondeo and a Ford Focus - near Junction 6 in Lewknor, Oxfordshire.
The driver and a passenger in the Forester, both in their 80s, and the driver of the Mondeo, a man in his 30s, died.
Videos filmed before the crash and posted on social media show motorists travelling in the outside lane of the motorway being forced to swerve to avoid a collision with the Subaru.
Senior investigating officer Sergeant Beth Walton, from the Serious Collision Investigation Unit of Thames Valley Police, said: “We are in the early stages of the investigation, in which sadly three people died, and our thoughts are with their families.
“We are in the process of contacting witnesses who provided a report to us and are grateful for their support.
“I would ask anyone who has footage not to share it and to remove it from social media out of respect for the families and friends of the people who died.”
Sonia Thomson, from Staffordshire, was driving in the outside lane of the motorway when the realised the Subaru “was just heading towards me”.
Ms Thomson, who works as cabin crew for British Airways, said the car was “going so fast” and “it was almost past me in the blink of an eye”.
The crash happened shortly after her encounter with the car.
“Someone must have been looking after me because 10 to 20 seconds later and that could have been me,” she said.
Ms Thomson added that the incident “doesn’t make sense” as she believed someone who accidentally drove in the wrong direction on a motorway “would get yourself to the hard shoulder and call for help”.
Others who saw the chaos took to Twitter to describe what happened.
Liz Hindmarsh posted: “My husband had to swerve into the middle lane otherwise he’d have been hit.”
Before news of the deaths was announced, Oliver Hayes wrote: “We also had to swerve, seemed at least 70mph driving head on in our lane at junction 8... did not look accidental.
“Called the police who said they’d had multiple calls by that time. Scary stuff hope no fatalities but looked inevitable the way they were driving.”