A driver has been reported on suspicion of driving without due care and attention after a serious crash in Kewferry Road.
The collision between a Toyota and Vauxhall occurred near to the junction with Rickmansworth Road in Northwood.
Police in Hillingdon arrived at the scene after being called at 11.28pm on Wednesday night (May 2).
Rickmansworth Road was closed while police investigated and cleared debris from the road. The road remained closed until around 4am.
The London Ambulance Service arrived alongside the London Fire Brigade, and the driver of one of the cars, in his 20s, was treated at the scene for minor injuries.
The other driver, a 40-year-old man, was reported by officers on suspicion of driving without due care and attention.
Police have made no arrests and continue to investigate the crash.