A cure for asthma is on the horizon after scientists discovered a genetic switch which prevents the condition.

The research carried out at the University of Southampton, discovered that the gene ADAM33 plays a crucial role in causing the twitchiness and inflammation of airways that triggers an attack.

The gene makes an enzyme which usually attaches to the muscles in the airways helping to repair and regenerate damaged areas.

But the enzyme can become detached and 'go rogue' travelling around the lung and sparking the unnecessary production of new muscles and blood vessels which cause the airways to narrow – a process known as airway remodelling.

Scientists traditionally through that it was allergens – like pollen - that triggered airway remodelling, inflammation and eventually asthma attacks. But they could never explain why lots of people with allergies never get asthma.

Now scientists believe that it takes the combination of the rogue gene and an allergen to trigger an attack.