A Met Police officer was attacked while pursuing a suspect in north-west London.
Police had been pursuing a vehicle in Dartmouth Road, West Hendon, shortly after 19:00 BST when one occupant got out.
Scotland Yard confirmed one officer, who found the suspect in an alleyway, was seriously assaulted during a “struggle”.
The suspect fled but was later arrested on suspicion of attempted murder.
A force spokesperson said the officer, whose injuries are not thought to be life-threatening, had not been stabbed.