London Fire Brigade (LFB) have confirmed that ten fire engines and around 70 firefighters are tackling a fire on Brockley Hill in Stanmore.
It is reported that a disused two-storey outbuilding situated to the rear of a hospital is alight, according to a post on the LFB incidents page.
The Brigade was called at 1705. Crews from Stanmore, Mill Hill, Kentish Town, Finchley, Paddington and surrounding fire stations are at the scene. Hertfordshire Fire & Rescue Service is also in attendance.
The cause of the fire is unknown at this time.
