CRASH investigators are trying to establish the cause of a three-vehicle accident in which two motorcyclists were killed.

Police are appealing for witnesses to the collision, which occurred on the A326 Marchwood Bypass at its junction with Twiggs Lane at around 6.15am yesterday.

The A326 - one of the busiest routes in the New Forest - was closed for more than six hours while the emergency services dealt with the incident.

A blue Mercedes Sprinter van was involved in a collision with a black Honda motorcycle and a white Yamaha bike.

The two motorcyclists, a 38-year-old man from Gosport and a 49-year-old man from Southampton, died at the scene. Police say their next of kin have been informed and are being supported by specialist officers.

The closure of the A326 resulted in hundreds of drivers having to take alternative routes to work. Several roads in the Marchwood area, including Bury Road, Main Road, Normandy Way, and Trotts Lane were reported to be heavily congested northbound.

The accident also resulted in the temporary closure of Marchwood Infant School.

Posting on social media staff said: "After consultation with the police, we have had to make the difficult decision to close the school today as a serious road traffic incident has closed Twiggs Lane.

"We have been advised that this closure is likely to remain in place for most of the day.

"Many staff are unable to get into school and much of the local area is gridlocked. Police are anticipating that this will take several hours to clear. Our thoughts go out to those involved in today's incident."

However, a later post said the school would reopen at 12.30pm.

Marchwood county councillor David Harrison said: "A very sad day and thoughts are with those were involved and for the friends and family of the deceased.

"Whenever something like this happens there is a rush to judgement about whether the existing road structure is safe, or would be better if changed.

"I have no idea of the circumstances of the incident and would not draw any firm conclusions until the full investigation has been completed."

Appealing for witnesses a police spokesman said: "We are keen to hear from anyone who may have been in the area at the time and saw what happened, or saw the three vehicles driving in the area prior to the collision.

"Any information you have, no matter how insignificant you feel it might be, could help aid our investigation."

Anyone with information can call Hampshire police on 101, quoting reference number 44210400737.