A crackdown on traders selling knives to kids has been hailed a success in Streatham after a dramatic drop in the illegal activity.

An undercover operation took place in Streatham and Brixton over the May half term and saw no shopkeepers sell 15-year-old volunteers a knife.

A similar sting operation 18 months ago saw 11 out of 29 shops sell a knife to underage kids, including every shop tested in Streatham High Road.

Bernard Conmy from Lambeth trading standards said: "The fact not a single shop we visited in our last operation was willing to sell a knife to our underage volunteer is really heartening, and seems to be a clear sign that our Lives not Knives campaign is working."

The campaign involved businesses signing up to a charter, which required them to ask anyone who looked under 21 for ID, regular test-purchasing operations, and trading standards officials contacting shops to ensure they understood the law.

Volunteers aged 15 years old tried to buy alcohol, tobacco, or knives during the three day operation.

Some 12 per cent of shops wrongly sold alcohol, and 4 per cent wrongly sold cigarettes.

Pirate DVDs were also found on display for sale at an off licence and were confiscated.

One arrest was made of an illegal immigrant working at an off licence.