There has been a dramatic rise in the number of young people being treated for addiction to legal highs.

Public Health England recorded over a 170% increase in those under 18 and dependent on synthetic cannabis, known as "Spice" which can be bought openly in high street shops.

Government legislation to ban such substances is expected to come into effect in the coming weeks but there are concerns it may not stem the level of addiction.

UK affairs correspondent Jeremy Cooke reports.