The incident has occurred at the junction with Knighton Shute, with 1 vehicle going into the back of another.
The Isle of Wight Ambulance Service are on scene with an ambulance crew and officer. Police are also on scene.
Emergency services were alerted to the crash at around 09:10.
The road remains open in both directions at this moment in time but traffic is delayed in the area.
UPDATE @ 09:30 – The Downs has now been closed in both directions by Police.
3 appliances from the Isle of Wight Fire and Rescue Service – including the rescue tender – have arrived at the crash scene and are working to extricate at least 1 person.
Island Echo understands the driver of one of the vehicles is complaining of neck pain and, having got back into the rear of the vehicle, now requires extricating by firefighters.
The road is expected to remain closed for at least 60 to 90 minutes.
UPDATE @ 10:05 – 1 person has been extricated from a Ford KA by means of a full roof removal and they are now being conveyed to St Mary’s Hospital by ambulance.
Fire crews are standing down from the incident.
The road is expected to re-open once recovery of the vehicles has taken place.
UPDATE @ 10:20 – It has been confirmed that a third vehicle was also involved in the incident, an Audi A3. The vehicle has sustained minor damage.
The other vehicle involved was a BMW.