Five men have been arrested and a man is in critical condition after an accident believed to have involved a quad bike.

Police were called to reports of a man lying in the road with injuries at Oliver Road at Thurrock Trade Park at around 3pm yesterday.

The injured man, who was rushed to the Royal London Hospital, is currently in a critical condition.

First enquiries found the man was riding a quad bike before he was injured, but no quad bikes were present at the scene.

Five men in their 20s, who were with the injured man, were arrested on suspicion of perverting the course of justice.

Police are now seeking witnesses to the incident.

Inspector Steve Brewer, from the Roads Policing Unit, said: "Although all the indications are the man has come off a quad bike there was no such vehicle at the scene and we believe it has been deliberately removed.

"Five men, in their 20s, who were with the injured man have subsequently been arrested on suspicion of perverting the course of justice and have been taken to police stations for interview.

"The area where this happened is quite popular on a Sunday with quad bikers and I would like to hear from any other road users who were in the Oliver Road area at the time the man was injured who can tell us what they saw.

"I also want to hear from anyone who believes they know where the quad bike this man was riding has gone.”

Witnesses or anyone with information can contact Essex Police on 101 quoting incident number 568 of February 7.