The driver involved in the Croydon tram crash will not be charged with gross negligence manslaughter, police have said.

There will also be no charges of corporate manslaughter brought against Transport for London or the operator Tram Operations Ltd, a subsidiary of FirstGroup.

British Transport Police said: “Every scrap of possible evidence has been scrutinised.”

Seven people were killed and 51 were injured when the tram derailed in south-east London on 9 November 2016. It came off the tracks while travelling at almost four times the speed limit in darkness and heavy rain.

The driver, Alfred Dorris, of Beckenham, south-east London, was arrested at the scene and questioned on suspicion of manslaughter. An investigation found that he may have drifted into a “microsleep” before speeding round a sharp bend at 45mph.

The Rail Accident Investigation Branch (RAIB) said it was “probable” Dorris “temporarily lost awareness” on a straight section of track and may have fallen into a microsleep for up to 49 seconds.