Asthma is characterised by inflammation of the airways, associated with hyper-responsiveness of the airway smooth muscle. Typical symptoms are breathlessness, wheezing and coughing. Many patients achieve good levels of control but others do not, putting them at risk of acute exacerbations. This can lead to increased hospital admissions and, in more extreme cases, episodes of respiratory failure and even death; 1,143 people died from acute asthma in 2010 (Asthma UK, 2013).