MYSTERY surrounds how a man ended up seriously injured on a Teesside street.

Police are appealing for witnesses to come forward after the 21-year-old man was discovered on Normanby High Street, in Normanby, near Middesbrough, yesterday (Sunday, November 16).

Officers believe he was injured in a motorbike crash, but it is not known whether he was the driver or pillion passenger.

The man was found by an ambulance crew at about 4.30am and he is currently in James Cook University Hospital, Middlesbrough, in a critical condition.

A motorcycle was recovered near to where the man was found and police believe no other vehicles were involved.

A 27-year-old man was arrested in connection with the incident and bailed pending further enquiries.

Police would appeal for anyone who may have information to contact them on 101.