Senior author Dr Stephen Liggett said: ‘I initially thought the bitter-taste receptors in the lungs would prompt a ‘fight or flight’ response to a noxious inhalant causing chest tightness and coughing so you would leave the toxic environment but that’s not what we found.

It turns out that the bitter compounds work the opposite way from what we thought. They all opned the airway more profoundly than any known drug that we have for treatment of asthma or chronic obstructive pulmonary disease.

‘This could replace or enhance what is now in use and represents a completely new approach.