Two people were shot dead in London within eight hours amid police warnings that gangs are finding increasingly inventive ways to import firearms.

A 25-year-old man is believed to have accidently shot himself when a bullet ricocheted off the windscreen of a parked car in broad daylight.

One eyewitness said the victim "came to shoot someone else, but he ended up shooting himself" on a busy street in Sydenham, south London shortly before 4pm on Sunday.

A 56-year-old local resident said: "The bullet bounced off a car window. After it happened, the boy he came to shoot stood there filming him."

A shopkeeper said a group of men had been sitting in the car but ran off when the other man approached, prompting him to start smashing the vehicle with the back of a gun.

“As he was hitting the windows the gun went off and he shot himself,” he said. “That’s what we’ve been told.”