Asthma could be cured within five years after scientists discovered what causes the condition and how to switch it off.
In a breakthrough which could change the lives of Britain's five million sufferers, researchers at Cardiff University and King's College London identified which cells cause the airways to narrow when triggered by irritants like pollution.
Crucially, drugs already exist which can deactivate the cells. They are known as calcilytics and are used to treat people with osteoporosis.
"Our findings are incredibly exciting," said Prof Daniela Riccardi, from Cardiff University School of Biosciences.
"If we can prove that calcilytics are safe when administered directly to the lung in people, then in five years we could be in a position to treat patients and potentially stop asthma from happening in the first place."