A teenager is fighting for life after the scrambler bike he was riding veered off the road and hit a tree.
The 18-year-old was rushed to hospital when his orange off-road bike crashed shortly before 5pm on Sunday.
Emergency services were called to the site of the collision on Warrington Road, in Wigan, close to the junction with Dale Street.
Greater Manchester Police issued an update on Monday to say that his condition was now critical and he was fighting for his life.
In a statement, officers said they are appealing for witnesses to the crash to come forward to help with enquiries.
The force added: “Police are appealing for information after a man has been left in a life threatening condition following an off road bike collision in Wigan.
“At around 4:40pm on Sunday 30 August 2020, police attended at the scene of a collision on Warrington Road in Ince, near to the junction with Dale Street.
“Enquiries have established that an 18-year-old man had sustained serious injuries after falling off of an orange KTM 200 EXC off road bike before travelling across the carriageway and colliding with a tree.
“Emergency services attended and the man was taken to hospital with a serious head injury where he remains in a life threatening condition.
“No arrests have been made and enquiries are ongoing.”
Police Constable Karl Horner, of GMP’s Serious Collision Investigation Unit, said: “This is a tragic accident which has sadly left a man fighting for his life, and we are keen to establish the full circumstances surrounding this collision.
“This collision happened on a busy stretch of road in broad daylight, so I am confident that there are a number of witnesses who may have valuable information or dash cam footage.
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“If you were in the area at this time and have any information that could assist police with their enquiries please do not hesitate to get in touch.”
Anyone with information can contact police 0161 856 4741, quoting incident number 2167 of 30/08/2020.
Reports can also be made anonymously to the independent charity Crimestoppers on 0800 555 111.