How Healthy are E-Cigarettes?

E-cigarettes seem to be everywhere nowadays. Invented by a Chinese pharmacist and patented in 2004, they first went on sale in 2010 and are now the most popular way to quit smoking in the UK. But although there's no smoke, there's certainly a fire of controversy around e-cigs, as Kat Arney found out when she spoke to Linda Bauld, professor of health policy at the University of Stirling, who chaired a panel discussion about e-cigarettes at the NCRI Cancer Conference.