The driver, a 42-year-old female ambulance technician, and the patient, an 88-year-old man, were pronounced dead at the scene.
A male crew member and a male relative of the patient remain in hospital both in a serious condition.
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James Wright has Monday's forecast for the east of the ITV Meridian region.
James Wright has Monday's forecast for the west of the ITV Meridian region.
Santa is not the only one who has an epic journey to make on Christmas Eve. A Sussex man is to cycle 500 kms to raise money for charity.