A paramedic and an elderly patient were killed when an ambulance crashed into a tree.
For reasons yet to be established, the ambulance left the road and hit a tree, Hampshire Police said.
The driver of the ambulance - a female paramedic - and an elderly male patient travelling in the rear of the vehicle died at the scene.
A male crew member and a male relative of the patient, who were both in the back of the ambulance, suffered serious injuries.
"Next of kin for those involved are in the process of being informed," a police spokesman said.
More top news
The working poor and elderly fear they will be clobbered when the Chancellor announces his Autumn Statement tomorrow, Penny Marshall writes.
Computer giant Dell apologises for hacking vulnerability and releases instructions on how to remove the rogue eDellRoot Certificate.
Douglas McTavish believes a faulty tumble dryer may be to blame for his 39-year-old son's death in a flat fire last year.