A cannabis addict who bought an antique revolver on the internet and then manufactured his own bullets during lockdown, has been found guilty of murdering Sergeant Matt Ratana in a south London custody centre.

Louis De Zoysa shot dead the 54-year-old Metropolitan Police officer in September 2020 as he was being processed at Croydon police station following his arrest for carrying drugs and ammunition.

Lawyers for the 25-year-old had argued he did not intend to kill the New Zealand born officer and had been in the grip of an “autistic meltdown” when the gun went off.

But jurors at Northampton Crown Court rejected his plea of diminished responsibility and convicted him of murder.

Jurors deliberated for just over five hours over two days before unanimously convicting Louis De Zoysa, who listened to the verdict sitting in a wheelchair in the secure glass-fronted dock.