Police dedicated to hunting dangerous dogs like those used to attack Seyi Ogunyemi have seized more than 1,070 animals over the past 12 months.
Officers at the Metropolitan Police's status dogs unit said the number of violent dogs kept in the capital is soaring.
Sergeant Ian McParland, who leads the team, said the problem is so big his colleagues must prioritise dogs that pose the biggest risk.
As a result, some 900 pitbulls have been taken away by police alerted by complaints from neighbours, dog owners and park users.
Mr McParland said the problem is fuelled by gang violence, insecurity among young people and cultural influences like gangster rap music and videos.
He said: "If you look at most local authorities, you will see there are more dog on dog attacks, animals being injured, particularly by bull breeds fighting in parks.
"We are getting more children's play areas ripped apart and generally more antisocial behaviour."
The status dog unit, made up of a sergeant, five constables and civilian worker, is responsible for targeting those who breed, sell and fight dogs.
They are supported by a senior RSPCA officer who uses his expertise and enforcement powers to ensure dogs are kept in the right conditions.
Asked why people keep aggressive dogs, Mr McParland said: "The answer is in education, in changing people's social attitudes. Once we understand why people have these dogs, then we can help.
"There are some obvious examples. If you have a 13-year-old daughter and you live on an estate where she is coming home at 8pm then parents might encourage them to get a dog.
"Perhaps the parents who are telling them not to have knives are encouraging them to have dogs.
"A lot of gang members have dogs and they fight them among themselves. But if you look at the way these young people live, then the dog is just an extension of their personality.
"A lot of them love their dogs, they might fight them but they are only extending what they all do between themselves."
Jon Eachus, of the RSPCA, said: "The whole dangerous dogs situation, irresponsibility with dogs, has increased 10-fold in the last couple of years.
"It has just been blown all out of context. It is just too easy to acquire them, it has become the in thing to have these dogs. A couple of years ago we did not have this sort of problem.
"Some of it has to do with rap music and what has come across from North America. It affects the younger generation. The problem is, what is not coming across is how to look after them."