South Central Ambulance Service said it was called by police just after 1pm after the woman - whose age has not been revealed – was found in a life-threatening condition on the corner of London Road and Inhurst Road in North End.
An ambulance service spokesman said: 'We sent two rapid response vehicles, an ambulance and the Hampshire and Isle of Wight Air Ambulance critical care car to the incident.
‘After initial treatment at the scene the patient was then taken to the Queen Alexandra Hospital – still in a critical condition.’
Police said they were called at 1.06pm with reports that a woman was seriously unwell in Inhurst Road.
They confirmed she has been taken to hospital and added: ‘No third party involvement or criminal offences have been identified.’
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