The emergency services were called at around 3.30pm yesterday (January 14) to Sumpter Close, near Finchley Road station.
Paramedics treated an unwell person and took her to hospital “as a priority”.
The Met Police has indicated that it was not a criminal incident.
A London Ambulance Service spokesperson said: “We were called at 3.39pm yesterday (14 January) to an unwell person in Sumpter Close, NW3.
“We sent an ambulance crew, paramedics in fast response cars and an incident response officer to the scene.
“We treated a patient at the scene and took her to hospital as a priority.”
