A police officer has been stabbed with a machete while attempting to stop a van in Leyton, east London.
The male officer in his 30s was stabbed multiple times in what police said was as a “sudden and brutal attack”, but used his Taser to subdue the suspect.
The alleged attacker was arrested by another officer following the stabbing, which happened shortly after midnight.
The injured officer has been taken to hospital and is believed to be in a critical but stable condition.
The Metropolitan Police said uniformed officers had attempted to stop a van on the junction between Coopers Lane and Leyton High Road.
The vehicle failed to stop but the driver then got out and injured the officer, it added.
Insp Julia James from North East Command Unit said: “This was a sudden and brutal attack on a uniformed officer carrying out their duties. What began as a routine vehicle stop has transformed very quickly and unexpectedly into an unprovoked attack with a weapon.”
A man in his 50s was arrested at the scene on suspicion of GBH and taken to an east London police station for questioning. He did not require hospital treatment.
Pictures posted on social media showed a heavy police presence in the Leyton area.
Police have said there is nothing to suggest the incident is terrorism related.