We were called at just before 12.20pm to reports of a road traffic collision on Warren Lane, Harrow.
We sent two ambulance crews, two single responders in cars, a duty officer and London's Air Ambulance to the scene.
Sadly one patient was dead at the scene.
Our staff treated one patient for chest injuries who was taken to the Royal London hospital and another patient was treated for minor injuries and taken to Northwick Park hospital.
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The 24-year-old was unarmed and the incident is not being treated as terror-related.
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