A sports and outdoor equipment store in Wandsworth has been fined £20,000 after they were caught selling a knife to a teenager.

Decathlon in Wandsworth’s Southside shopping centre allowed the youngster to buy a foldable lock-knife with an 8cm stainless steel blade.

The purchase was part of an undercover trading standards operations to make sure local shops were complying with laws banning the sales of knives and blades to young people.

Most sale assistants refused the sale of the knife to the 16-year old, but Decathlon sold the knife which is described as “very sharp and durable” and “simple, strong and cuts very well” on their website.

Days before the purchase, a trading standards officer visited the same branch to remind staff that it was illegal to sell knives to anyone under 18.

While buying the knife at Decathlon, the youngster spoke to two different sales assistants who both didn’t challenge her age.

Trading standards officers later visited the store to question the staff involved, the sales assistant who processed the transaction said that he had never received training about knife sales.

The store manager said he had also not received any training about the law on knife sales to under 18s.

Wandsworth Council prosecuted Decathlon (UK) Ltd at Lavender Hill Magistrates Court last month. After pleading guilty the company was fined £20,000 and ordered to pay the council’s legal costs of £1,868.

Paul Browne, Wandsworth’s Trading Standards and Licensing Manager said: “Knife crime is a serious problem in London so it’s absolutely vital that shops comply with the law and do everything they can to prevent knives and blades getting into the wrong hands.

“This was a case of very poor practice by staff at this Decathlon branch and it could have had tragic consequences.

“Decathlon has around 30 stores in the UK, so it’s a large scale and popular retailer, yet their procedures were totally inadequate to prevent the sale of a potentially lethal weapon to a young person. This failure has resulted in a steep learning curve for the business, whose procedures have now been drastically overhauled to prevent any further illegal knife sales in the future.”

A spokeswoman at Decathlon, Wandsworth said: “Now we have knives in safes and have no knives on the sales floor. All the team are receiving training about sales of knives and at the tills there is a message reminding sales assistants to ask for ID.”