Police were alerted to the stabbing of a 15 year old boy on Stoke Newington Common at 2.10 pm this afternoon.
The victim has been taken to an East London hospital suffering stab wounds to his chest and his current condition is unknown.
No arrests have been made.
Brooke Road in Stoke Newington is now closed between A10 Rectory Road and Bayston Road.
Bus routes 73, 106, 393 and 476 are affected in the area and are subject to delays and diversions.
UPDATE 8:00PM : A police spokesperson has confirmed the teenager is in serious but stable and has non life threatening injuries.
A teenager has been arrested and is being questioned at a police station.
Roads have been re-opened.