UPDATE: The closures were lifted at around 12.30am this morning (Wednesday, July 4).
Previous details -
We were called at 9.19am following the collision involving a lorry, a van and a car on the A34 southbound carriageway.
The collision has totally blocked the southbound carriageway just out of Bullington and crossed over onto the A30, which runs parallel.
The southbound carriageway of the A34 is closed between the A303 and the A27.
The A30 is also closed in both directions.
We can confirm that one person has died, two people have been taken to hospital with serious injuries and one person has been taken to hospital with minor injuries.
Investigations are ongoing into the exact circumstances of the collision and as a result of this and the need to ensure the road is safe before it is reopened.
We are working with our colleagues from Highways England to ensure we get the road open as soon as possible.
We are dealing with a complex recovery operation and there is extensive damage to the crash barriers which Highways England will need to repair before closures can be lifted.
We would like to apologise for any inconvenience caused and urge motorists to avoid the area if possible.
Diversions are in place. For motorway traffic diversion are via the A30 and M3. For non-motorway traffic diversions are via the A33.
We will update with more information when we have it, so please keep checking our Facebook and Twitter pages for the latest updates.
Thank you for your patience while we deal with this incident.
Officers would like to speak to any motorists who were driving in either direction of the A34 at around 9am this morning as they may have information that could help with the ongoing investigation.
Anyone with information is asked to contact us on 101, quoting incident number 238.