We performed a retrospective cohort analysis comparing trends in low global warming potential (GWP) inhaler prescribing in primary care in England, Scotland, Wales and Northern Ireland between 2018 and 2024 using national prescribing data. There was little change in England, a reduction from 36.6-31.0% in Scotland, a reduction from 36.7-33.2% in Northern Ireland, and an increase from 30.8-41.1% in Wales. Only in Wales was there a simultaneous reduction in high GWP inhalers and an increase in low GWP inhalers. Over the time period of the study there has been a saving of 20,303 tonnes of carbon dioxide equivalent in Wales.