A woman who was once slashed in the face has warned parents of how easy it is for youngsters to buy knives online.

Sarah Armstrong, 31, was sliced with a knife across her cheek 12 years ago in Beckenham when a gang demanded her phone.

"It was terrifying, and I didn’t leave my house for a year afterwards," she told News Shopper. "I had a scar down my face; it was horrendous."

Determined not to be beaten, Sarah set up Say No 2 Knives in 2008.

After a 22-year-old man was stabbed do death near her home in Anerley last November, Sarah decided to investigate how difficult it is to buy knives.

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She said: "I couldn’t believe how easy it was.

"It is disgusting. People take for granted how easy it is."

Sarah was able to obtain four knives from a foreign online shopping company without having to provide age verification.

She was surprised to learn that when the package arrived, the goods were labelled as things like tweezers, card toys, pendants and wallet holders.

The knives arrived in her post box meaning she didn’t even have to sign off on them.

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Sarah now plans to present her evidence to the Metropolitan Police.

"I have a full-time job," Sarah said. "But I can’t let this slide, it has really angered me. I was hoping the police would turn up at my door to ask why I am ordering so many knives."

Sarah is still waiting for some more knives to arrive at her home in Penge.

Having lived most her life in Beckenham, Sarah said it was still a nice area, but that people are getting scared because of how "ruthless" kids are becoming.

She had the following advice to parents of teenagers.

"My biggest concern for parents would be to check what is coming into the house. These cheap and cheerful websites are giving away good quality knives and you only have to pay for postage and delivery.

"They could do a lot of damage. Parents need to check what is in the package, and not rely on what the packaging says."