A feasibility RCT comprising two groups:

1. Intervention (SELF-BREATHE in addition to standard NHS care)
2. Control group (standard / currently available NHS care)

Inclusion Criteria:

• Adults ≥ 18 years of age, with the ability to read and type in English
• Access to a computer, or tablet or smart phone, with internet access and the ability to email
• Chronic breathlessness (CB) defined as; breathlessness that persists (>3months) despite optimal pharmacological treatment of the underlying disease including cancer, chronic obstructive pulmonary disease (COPD),asthma, interstitial lung disease (ILD), bronchiectasis, cystic fibrosis (CF) chronic heart failure (CHF), sickle cell disease, chronic renal/ liver failure or post COVID-19
• Chronic breathlessness at rest or on exertion; MRC dysponea score >2
• Willing to engage with short-term self-guided internet-based breathlessness intervention (SELF-BREATHE)
• Able to provide informed consent

Exclusion Criteria:

• Breathlessness of unknown cause
• A primary diagnosis of chronic hyperventilation syndrome
• Currently participating in a rehabilitation programme, e.g. pulmonary/cardiac rehabilitation

Single blind