Sputum Colour Charts to Guide Antibiotic Self-treatment of Acute Exacerbation of COPD (Colour COPD)

Inclusion Criteria: * Clinically diagnosed COPD, confirmed by a medical record of post-bronchodilator spirometry denoting obstruction. * ≥2 AECOPD in the 12 months prior to screening according to the patient or ≥1 hospital admission for AECOPD (i.e. Global Initiative for Chronic Obstructive Lung Disease- GOLD; C or D). * Able to safely use SM plan in the view of their usual care practitioner * Able to use sputum colour chart; this will be confirmed by a sight test if there is any doubt on initial assessment by the usual care or research team. Patients who report being colour blind will have their ability to use the chart tested at the screening visit. * Written Informed consent given Additionally, to participate in the E-diary sub-study. - Access to smartphone/tablet and an email address. Additionally, to participate in the Sputum sub-study. \- Chronic bronchitis, defined by self-reported sputum production for at least 3 months in each of 2 consecutive years or more. Exclusion Criteria: * Household member already participating in the study.