Police have warned of a growing street culture of owning dangerous dogs and their increasing use as weapons in crime.
By Phil Kemp
BBC Five Live Report
Pit bulls: Seen as a fashion accessory by some
As a Liverpool youth with a macho dog explains: "It's the fashion, innit. It's the fashion.
"All the young lads are walking around with dogs now, aren't they. It's just a fashion accessory, isn't it. It makes them look good, doesn't it. That's just how it is, isn't it."
Another of the attractions for some young people is that they are seen as a form of protection.
"They're basically a legal weapon," says 15-year-old Lil from north London.
"They could do as much damage as a firearm but they're legal. That's the best thing about them."
The latest statistics from 2005 show 403 people were found guilty of allowing a dog to be dangerously out of control in a public place and injuring somebody.
That's up from 260 in 2000.
The Dangerous Dogs Act introduced in 1991 outlawed pit bull terriers as well as other dogs "appearing...to be bred for fighting or to have the characteristics of a type bred for that purpose".
It is not just illegal dogs that are becoming popular with young people. Battersea Dogs Home says around 1,500 of the nearly 8,000 dogs they took in during 2005 were either Staffordshire bull terriers or Staffordshire crosses.
Dog refuges are putting the rise in the number of rescued macho dogs down to over-breeding by irresponsible owners.
Harvinder Heer, 20, was the victim of a dog attack in Birmingham in November last year. He is convinced that pit bulls were deliberately set on him when he was set upon by a gang.
"At first they weren't doing anything but then I heard one of them say 'kill' and that's when the dog switched, scratching my leg and biting me," he explained.
"I couldn't really feel the kicks or the shotgun being smashed in my face, all I could feel was the one dog that had its teeth in my thigh."
He and his friends were walking through a park and got involved in an incident with another group which had two dogs.
The Dangerous Dog Act outlawed pit bulls
"I've had to have 10 stitches on my forehead, 10 stitches on my head, I've had minor plastic surgery just by my nose there, and a dog bite as well on my leg. The scars on my head will stay there for life."
Dogs like pit bulls are also being used in robberies across the country, according to Ch Supt Bob Gittens of Merseyside Police.
"Nationally, I think we've seen some incidents where they're used as weapons in robberies. We've had a number of cases where that's happened.
"The underlying problem is that it now appears to be a fashion accessory.
"It's part of the culture to have a dangerous type dog, a pit bull or a derivative of a pit bull as sort of an extension of your sort of commodity that you need to be somebody on the streets."
Dice, 15, from north London owns a "half American Staff-Half American Pit Bull". He says dogs have been used for robbery in schools and that police were questioning dog owners in the area to try to stop the attacks.
He told BBC's Five Live Report that 11-year-olds starting secondary school were particularly vulnerable to attack from thieves.
"They know if they go to a school it's a 110% they'll see someone with a phone.
"They threaten them and say 'he'll bite if you don't give me your phone'."
Phil Kemp's report A Yob's Best Friend was broadcast on Five Live Report on Sunday at 1100 GMT. It is available on the Five Live Report website.