Use of potentially lethal Tasers on children by the Metropolitan Police has risen nearly six-fold over four years, campaigners revealed yesterday.

Police used the controversial stun guns on children 131 times between 2008 and 2012 across 21 London boroughs, rising from nine instances in 2008 to 53 in 2012.

London Assembly Labour group police and crime spokeswoman Joanne McCartney said: "This report is very alarming. Tasers should not be used on children. What's even more worrying is that the figures in this report only go up to 2012. Since then there has been a significant roll-out of Tasers to more police officers across London."

The figures, obtained by a Freedom of Information request by the Children's Rights Alliance for England (Crae), were published as part of a wider report into children and human rights in London.

They also showed a marked disparity between incidences of Taser use between boroughs.

In Croydon, Southwark, Lambeth and Lewisham children were tasered 51 times between 2008 and 2012, accounting for 40 per cent of the total.

Amnesty International UK arms programme director Oliver Sprague said: "The increase in Taser use on children in London is extremely worrying especially as the government's own safety advice warns that children are at a higher risk of suffering adverse effects from Tasers.

"Amnesty urges police forces to undergo enhanced training which should involve continual monitoring, assessment and clear guidelines to ensure Tasers are only used in life-threatening incidents."

Crae also found that while there had been a 66 per cent drop in use of stop and search powers against children between 2009 and 2013, that figure again varied greatly from borough to borough.

Green London Assembly Member Jenny Jones said: "Young people are suffering from both the excessive use by some local police of stop and search powers and from the growing use of tasers as a tool of compliance. Both are examples of the police overstepping what the powers are designed for."

She said the Met risked alienating another generation of young people due to heavy-handed use of stop and search and also called on the force's commissioner to explain the major increase of Taser use in certain boroughs but not others.