Dorset Police was called to reports of a road traffic collision on the B3091 near to Cole’s Lane, at approximately 11.05pm on Saturday 14 November.
A VW Golf was being driven from Shaftesbury toward Sturminster Newton when it left the road and struck a tree before coming to rest in the carriageway.
A short time later a Kia Picanto being driven by a local 20-year-old man was in collision with the Golf and the driver of the Golf, who had got out of his vehicle following the initial collision.
The driver of the Golf, a 30-year-old man from the Shaftesbury area, sustained serious potentially-life-threatening injuries and was taken to Southampton General Hospital for treatment.
The driver of the Kia was arrested on suspicion of motoring offences and has been released under investigation while enquiries continue.
Police Constable Jay Griffin, of the Serious Collision Investigation Team, said: ‘I am appealing to anyone who witnessed either collision, or was travelling in the area at the time and saw the vehicles immediately prior to the incident, to please contact Dorset Police.
‘I would also ask motorists who were nearby to check their dashcam footage and get in touch if they captured the vehicles involved travelling along the B3091.’
Anyone with information is asked to contact Dorset Police at www.dorset.police.uk, via email [email protected] or by calling 101, quoting occurrence number 55200172065. Alternatively, or alternatively to stay 100% anonymous, contact the independent charity Crimestoppers online at Crimestoppers-uk.org or call freephone 0800 555 111.