We performed a retrospective cohort analysis comparing the trends in low global warming potential (GWP) inhaler prescribing in primary care in England, Scotland, Wales and Northern Ireland between 2018 and 2024. Over the study period there was little change in low GWP inhalers in England and Northern Ireland, a reduction from 35% to 30.9% in Scotland and an increase from 31.7% to 38.7% in Wales. Only in Wales was there a simultaneous reduction in high GWP inhalers and an increase in low GWP inhalers in line with published national goals. These findings suggest that the approach taken in Wales to promote inhaler switching was effective and could be adopted in the other nations.