This clinical trial will investigate if home High-Flow Therapy (HFT) improves 12-month admission-free survival (time to readmission or death) following a severe exacerbation of COPD requiring hospitalisation. This is an area of unmet need, given the demonstrable limitations to current interventions which are costly, have extensive side-effects, limited availability and variable efficacy. If this this clinical trial demonstrates clinical and cost effectiveness of HFT, this technology could be rapidly incorporated into routine NHS clinical practice.