A grateful dad says his faith in humanity has been restored after a stranger prevented his young son and his friends from being mugged.

The boys, aged 13, were cycling on Petts Wood Road by the chiropractic clinic when a group of older teenagers blocked their way on the afternoon of bank holiday Monday.

Ben, who didn't want his full name used, told News Shopper his son was left "petrified" after the boys demanded their money.

"They surrounded them and grabbed one of my lad’s mates," Ben told News Shopper. "I think it was the smallest one and they began roughing him up.

"Then someone shouted out the window. I was so grateful because you just don’t know these days."

He added: "When I was a kid, we played knock down the ginger. Kids nowadays go around stabbing one another."

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Ben has thanked the man who prevented the situation from escalating and said police were informed of the mugging attempt.

He said it was a worrying time for parents and added that his son’s reaction proved how normalised muggings had become.

"When my lad got back, he said 'well I’ve expected it to happen because everyone gets mugged'.

"Christ, he’s 13 and shouldn’t be thinking of things like that."

The concerned dad said muggings were more common in the Crays or Orpington High Street but said Petts Wood was not short of crime either, particularly house break-ins.

He said he was worried for his son's safety but that he can't keep his boy locked indoors.

"I'm so worried for my lad," he explained. "I cant put a leash on him. I have to let him go out but I don't know how much further it would have gone if that guy had not shouted out from a window."

Ben Brown was the man from the window who helped the kids.

He told News Shopper he was standing in his flat when he heard someone saying “are you telling me if I check your pockets you’ll have no money on you”.

Mr Brown looked out of his window to find a boy crouching and an "Asian teenager with a hoodie" checking his clothes.

"That’s when I shouted 'what the f are you doing'," Mr Brown said.

He told the kids on bikes to go home to their parents before he went outside and rang the police.

Mr Brown, a father himself, felt compelled to help after being mugged in Orpington twice when he was younger.

"I’m just sick and tired of it," he said. "Who do these kids think they are? They were wearing designer clothes like Adidas and Nike and didn’t look stuck.

"It’s so upsetting, and Petts Wood is not that type of location. The kids were absolutely petrified."

Ben said he was grateful to the boy’s dad who got in touch.

After reporting the incident, police officers and Ben searched Petts Wood in an unmarked car but the teenagers were nowhere to be seen.