Police are appealing for witnesses to a collision that left three people injured, one of them seriously.
A black Honda Civic and a black Mercedes were reported to have been seen driving at speed on the M11 southbound between junctions 5 and 4, near Loughton and Woodford, shortly before 11.35pm on Sunday August 8.
The Honda was then in collision with a black and grey moped.
The rider, a 32-year-old man from north London, was taken to hospital with multiple injuries and remains in a stable condition in hospital.
A Toyota Prius that attempted to avoid the vehicles was then in collision with a Vauxhall Crosslander.
Two women inside the Toyota, who are both from east London, were injured. A 38-year-old woman suffered whiplash and a 48-year-old woman suffered a fractured wrist.
The drivers of the Honda, Mercedes and Vauxhall were not hurt.
The Honda driver, a 25-year-old man from Edmonton, was arrested on suspicion of causing serious injury by dangerous driving, drink-driving and racing on a highway
Two people connected to the Mercedes were also arrested.
A 28-year-old man from Edmonton in London, was arrested on suspicion of causing serious injury by dangerous driving, drink-driving, obstruction of a police officer and racing on a highway.
A 26-year-old woman from Finchley was arrested on suspicion of dangerous driving and racing on a highway.
They have all been released under investigation.
Anyone who saw the vehicles travelling on the motorway before the incident, or who has any dash cam footage, is asked to contact Chigwell Roads Policing Unit quoting incident 1302 of 8 August.
You can submit a report online at https://www.essex.police.uk or use the ‘Live Chat’ button to speak to an online operator between 7am-11pm.
Alternatively, you can call 101.
Information can also be given to independent charity Crimestoppers anonymously on 0800 555 111 or https://crimestoppers-uk.org