Two Met officers have been hospitalised in separate incidents in the space of just a few minutes.
One officer suffered a broken finger as he arrested a suspect after officers were called to two men “behaving supsiciously” in Clandon Close, Acton, at around 9pm on Saturday.
Police said the men were thought to be storing or accessing weapons.
Officers rushed to the scene and located the two men.
One of the men is said to have become aggressive towards the officers and a male constable suffered a broken finger as he detained the suspect.
The two men arrested and taken into custody are: a 28-year-old man on suspicion of assaulting the officer and a 51-year-old man on suspicion of possessing an offensive weapon after a crowbar was found nearby.
The Met said the officer has been discharged from hospital, but his hand injury will require ongoing treatment.
In a separate incident at around the same time, officers on patrol in Croydon began pursuing a Mercedes car after it failed to stop for police who had spotted it being driven erratically.
The vehicle stopped briefly in Lindfield Road, Croydon at 9.06pm.
A police spokesman said: “The driver then rammed the police car before colliding with an officer who was on foot. The officer, a male police constable, sustained serious injuries to his ankle and hip as well as head injuries. He remains in hospital.”
The Mercedes was driven “recklessly” away from the scene, stopping when it collided with a garden wall. The driver ran away, but was pursued on foot and detained moments later by officers from the Met’s Violent Crime Task Force.
The 25-year-old man was arrested on suspicion of GBH on the officer, dangerous driving, failing to stop and aggravated taking and driving away of the Mercedes. He was also found to be in possession of a quantity of crack cocaine.
Superintendent John Tibaldi said: “Both these incidents show that Met officers are committed to keeping Londoners safe - not only by responding to emergencies and other reports of crime but through targeted patrols and taking positive action to prevent crime in the first place.
“Police officers routinely put themselves in harm’s way on a daily basis, dealing with dangerous situations and violent people.
“Tackling violent crime is the Met’s top priority, and that includes dealing robustly with those who assault our officers and other emergency workers.”
Anyone with information about people who use violence, carry weapons or bring criminality to neighbourhoods can speak with local officers, call 101 or, to remain anonymous, contact Crimestoppers.