Vigilantes threaten to 'cleanly kneecap criminals'

A group of armed vigilantes in Northern Ireland is persuading parents to hand over their children to be shot as a punishment, if they have been involved in drug-dealing or anti-social behaviour.

The group, calling itself Republican Action Against Drugs, contacts families to say the offenders will be kneecapped "cleanly" if they go willingly.

Police say witnesses are too scared to come forward so it is proving hard to stop the vigilantes.

Newsnight's Liz MacKean reports from Londonderry.