It is not just rural council-backed services that have shrunk.
The miles on the buses - for commercial routes too - have been slowly dropping since 2010. There has been a drop of about 22% since 2010.
It is back on the rise but has yet to reach the same levels as pre-Covid.
Commercial bus miles decreased by a quarter between 2010 and 2025.
The government's own analysis shows that some change in mileage between commercial and supported might be down to post-pandemic changes.
Companies, for example, may have stopped non-viable services, with local authorities helping fund the routes instead.
The Confederation of Passenger Transport (CPT) said one of the reasons is bad traffic.
Worsening congestion on the roads has made buses slower and therefore less attractive to passengers. It can also make them pricier to run.
The organisation said buses outside London currently travelled on average at 11.7mph.
It said council support was needed most in rural areas, with lower populations making it harder to cover cost through bus fares and the countryside meaning "longer distances, more fuel".