Can mayor's social bonds remove rough sleepers?

Homeless charities stand to benefit from a new scheme - social impact bonds - aimed at getting private investors to help deal with vulnerable people.

London Mayor Boris Johnson hopes it will reduce the number of rough sleepers while easing the burden on the taxpayer but, is it too risky?

BBC London's Sarah Harris talks to Michael, a former rough sleeper who is getting help from homeless charity St Mungo's, Boris Johnson and St Mungo's charity worker Michael McCall.