Chronic Obstructive Pulmonary Disease (COPD) is a long term lung condition which causes breathlessness, tiredness, coughing and chest infections. People with the condition often find it difficult to carry out day to day activities and to live a normal life. In recent years people with COPD have been encouraged to self-manage their condition, for example by increasing their physical activity, which could help them to live their life to the full. Recent advances in technology have the potential to help people do this. The SMART COPD 'app' which is being used in this study has been developed, based on previous research and the views of people living with the condition, to help people with COPD increase their physical activity. Physical activity is known to be important in helping people with COPD to enjoy better health and to carry out activities. The current study will investigate whether or not the app could be used alongside existing health services, and whether or not people with COPD, as well as healthcare professionals, find the 'app' acceptable and easy to use.