Children as young as 13 have been able to illegally buy knives in undercover operations carried out across the capital, new figures reveal.

Some 96 shops, including stores in south London, sold knives and other blades to child volunteers during 724 tests carried out by London Trading Standards.

The results of the operation comes after four teenage boys were stabbed in Croydon within one week.

Borough Commander Chief Sup Jeff Boothe said the police, Croydon Council and community groups are working together well to tackle the ongoing knife crime problem.

RELATED: Croydon police on borough's knife-crime scourge after four teenagers stabbed in one week

Your Local Guardian:

More needs to be done to crack down on gang-related knife crime in London, police have said following the release of the Trading Standards figures

Your Local Guardian:

Video footage from a witness passing in a car captured the moment a teenager is appeared to have been stabbed in Albert Road, Croydon, last week

But Chief Inspector Gary Anderson, of the Met’s Trident Central Gangs Command, said more still needs to be done to continue to reduce the volume of gang-related knife crime.

It is illegal to sell knives to anyone under 18.

Trading standards carried out the tests using volunteers with an average age of 14, as part of the Met Police Operation Sceptre initiative aimed at reducing knife crime.

As a result, 19 traders have been prosecuted or have cases pending, while others received official warnings and compliance advice.

Stores in Croydon were among those prosecuted.

During the operation, assortment of five kitchen knives including a meat cleaver were sold to a 15-year-old, while another volunteer, also aged 15, was able to purchase two retractable blades.

RELATED: Mass brawl between more than 100 youths in Northumberland Heath leaves two teens in hospital

Your Local Guardian:

This set of knives were among those sold to juveniles in the undercover operation last year

CI Anderson said: "Through the delivery of education programmes and targeted work on boroughs we have successfully managed to reduce the volume of gang-related knife crime.

"However, more work still needs to be done and we remain committed to working in partnership with trading standards to prevent knives from reaching dangerous hands and to reduce the number of families devastated by knife crime in London."

There are a number of examples in recent months of youths involved in knife crime across south London.

In September last year, a brawl between more than 100 school children broke out in Bexley.

Shocking footage on social media showed the chaotic scenes as youths, some allegedly armed with knives and fire arms, clashed.

And in Croydon, where a shocking 23 people have been stabbed this year, four teenage boys were stabbed in brutal attacks last week.

RELATED: Norbury shop owner caught selling knives to underage children avoids jail

In Croydon, shop owner caught selling knives to underage teenagers in Norbury was the first retailer in the borough to be handed a prison sentence for the offence.

Shakeb Hakime, of Norbury Discount Store, London Road, was sentenced to 10 weeks’ jail, suspended for 12 months, after admitting the offence at Croydon Magistrates’ Court on 12th December 2016.

Following the conviction, Councillor Hamida Ali, cabinet member for communities, safety and justice, said: “Knife crime is on the rise in London and we must do all we can to keep potentially lethal knives out of the hands of those young people who feel compelled to carry them.

“Traders have a heavy duty of responsibility here, and should take every step to ensure that they and their staff don’t help knives to get into the wrong hands.”