 Bronchiectasis is a chronic chest condition which causes a persistent cough and frequent chest infections. One of the main forms of treatment is chest physiotherapy. Physiotherapy is thought to improve cough and help clear the airways of sticky sputum. Traditionally, physiotherapy techniques can be awkward, but recently a new device a simple mouthpiece, called the Acapella device has been developed to make physiotherapy practise easier. This study aims to assess how helpful regular physiotherapy using a new mouthpiece is in patients with severe bronchiectasis. 