An observational study comparing the effectiveness of lung volume reduction techniques for COPD. Many people with chronic obstructive pulmonary disease (COPD) remain very breathless and limited. In some patients, with the appropriate pattern of emphysema, an operation called lung volume reduction surgery is effective at removing the worst affected area of lung. New techniques have been developed where emphysema can be treated using a fibre-optic camera called a bronchoscope. Trials have shown that using a bronchoscope to place endobronchial valves into the airways can be very effective in carefully selected patients and the technique is now being adopted in hospitals across the UK. This study will collect data from people undergoing these procedures at hospitals across the UK to evaluate how well they work in practice and what factors at baseline influence response. Baseline, three month and 12 month follow up data will be collected. This will include lung function data, measures of exercise capacity, questionnaires about health status and CT scan results. Questions addressed will include: (1) What lung function improvement is seen in clinical practice? (2) What factors determine who is most likely to respond? (3) How safe are the procedures and what is the rate of complications? (4) What proportion of people undergoing bronchoscopic procedures require repeat procedures or surgery subsequently? (5) Does long term survival differ between people undergoing the different treatments? The study is supported by The British Lung Foundation and sponsored by Imperial College, London. By building collaboration, the establishment of the network will also produce a structure that will make evaluation of future bronchoscopic techniques easier bringing innovative treatments into play more quickly.