Officers investigating a one-vehicle collision on the A189 Spine Road have confirmed that the driver has now died in hospital.
At around 5.55am on Tuesday, police received a report that a silver Nissan Navara had left the road near Annitsford, south of the Moor Farm roundabout, and collided with a tree.
Emergency services attended and the driver of the vehicle was taken to hospital with life-threatening injuries.
However, police have today (Thursday) confirmed that the 37-year-old man sadly passed away in hospital yesterday afternoon.
Inquiries into the collision itself are ongoing but specialist officers are continuing to support the man's family.
Police are still appealing for any witnesses to the collision, or anyone who may have been in the area at the time, to get in touch with them.
If you can assist the investigation, or if you have any dashcam footage of the vehicle involved in the lead up to the collision, then contact police on 101 quoting reference 131 07/05/19.