Police and ambulance crews were called to the scene at shortly before 14:50.
The road has been closed in both directions with hard road closures in place, indicating the serious of the injuries sustained.
UPDATE @ 16:05 – Island Echo understands one person – a male motorcyclist – has sadly died in this afternoon’s collision. A further two people, believed to be the occupants of the car, have been injured.
Witnesses have described how the motorcycle involved has become wedged under the 4×4 vehicle.
The victim’s family have been informed and say he died instantly.
The road is expected to remain closed from South Down to Chine Farm camp site for several hours as mainland investigators from the Collision Investigation Unit are called in to examine the crash scene.
UPDATE @ 16:52 – The Collision Investigation Unit and the Road Death Investigation team are en-route to the incident scene, where a thorough forensic examination will be undertaken.
The road is expected to remain closed until at least 20:00 tonight.
UPDATE @ 21:00 – Hampshire Constabulary has issued the following statement.
We are appealing for information following a fatal collision on the Military Road, Atherfield, just before 2.40pm today (October 4).
A motorcycle, which was travelling North West along the road, was in collision with a Jeep Cherokee.
The 21-year-old rider of the motorcycle, Reese Mitchell of Brading, Isle of Wight, was pronounced dead at the scene. Next of kin have been informed.
The 70-year-old driver of the Jeep was arrested on suspicion of causing death by dangerous driving.
Police investigating the exact circumstances of the collision would like to hear from anyone who was travelling in the area around the time of the collision, particularly any drivers who may have seen the Jeep Cherokee and two motorcycles before the incident.
The road remains closed while police investigate.
Anyone with information is asked to call on 101 quoting Operation Poet. Alternatively call Crimestoppers anonymously on 0800 555 111.
UPDATE @ 22:30 – Military Road has now re-opened to traffic.