Expert: ISIL 'highly likely' to launch gas attack in London

Islamic State militants returning to the United Kingdom could launch a chlorine gas attack on trains, the London Underground or at a football match, according to a chemical weapons expert.

Hamish de Bretton-Gordon, a former commanding officer at the Joint Chemical Biological Radiological Nuclear Regiment, said the last two weeks in Syria and Iraq have seen the "most concentrated and deadly use of chemical weapons" since the 1980s Iran-Iraq War.