Scientists have called for urgent controls on the promotion and sale of e-cigarettes to children after finding high rates of usage among secondary school pupils in the region.

In a survey of more than 16,000 teenagers in north-west England, the researchers found that one in five students aged 14 to 17 had bought or tried e-cigarettes. Many of those who dabbled with vaping were already regular smokers.

Nearly one in 20 of the teenagers who bought or tried e-cigarettes had never smoked conventional cigarettes before, suggesting that vaping may have become a new activity to experiment with.

But the survey did not reveal who went on to become long term users of e-cigarettes, or whether students used the devices to help them give up traditional tobacco smoking.