The number of children tasered by the Metropolitan Police has risen almost sixfold over four years, according to campaigners.
The Children's Rights Alliance for England (CRAE) said Taser stun guns were used on 53 young people in 2012, signalling a sharp increase from just nine in 2008.
In Croydon, Southwark, Lambeth and Lewisham children were tasered 51 times between 2008 and 2012, accounting for 40 per cent of the total.
Overall, children were targeted 131 times between 2008 and 2012, according to figures obtained through a Freedom of Information request and published as part of a wider report into children and human rights in the capital.
Paola Uccellari, director of CRAE, said: "Children living in the same city are experiencing vastly different treatment, depending on where they happen to grow up, and this is not always linked to obvious explanations such as high child poverty or crime rates."
"For example, 70 per cent of the occasions on which children in London were tasered by police occurred in just a quarter of London boroughs.
"This suggests different approaches at the local level can have a big impact on many of the human rights issues facing children in London."
The report also found a difference between boroughs in the number of stop and searches.
In Southwark, 91 children were stopped on average a week compared to just 19 in a week in Kingston upon Thames, Merton, Hillingdon and Sutton.
In addition, children in London are imprisoned at almost twice the rate of children in England as a whole, according to CRAE.
The Met said the "number is in line with the general increase in the use of Tasers" in London.
A Met Police spokesperson said:"The increased use of Taser on under 18-year-olds is in line with the general increase in the use of Taser across the board which is as a direct result of the fact that over the past year taser-trained officers are now present on all 32 boroughs.
"Taser creates space between the subject and police, reducing the need for physical contact and also the risk of unintended or unnecessary injuries to all parties."
Just over 2000 Met police officers are trained and equipped to use Taser stun guns, which were introduced as "a less lethal option" in 2004.