Cuts to bus funding risk turning some areas into "transport deserts" with no services, campaigners have warned.
More than 500 routes were withdrawn or reduced across England and Wales in 2016/17, according to the Campaign for Better Transport (CBT).
Its analysis found that nearly £30 million was slashed from local authority-supported bus funding in the last financial year.
This budget is used to subsidise buses not provided by commercial operators, serving communities where no alternative route exists or extending the timetable into evenings and weekends when services would otherwise stop.
An estimated five billion bus journeys made in Britain in the year ending March 2016, accounting for around two-thirds of all public transport journeys.
CBT campaigner Lianna Etkind said: "Buses across the country have been hit hard by funding cuts. Year-on-year we are seeing more bus services lost, with some local authorities stopping supporting buses altogether.
"These cuts come on the top of cuts to school transport and the underfunding of free pensioner travel.
"Together these threaten the viability of whole bus networks and will lead to transport deserts in some rural and suburban areas where there is no public transport at all."
Martin Tett, transport spokesman at the Local Government Association (LGA), representing more than 370 councils in England and Wales, said local authorities "know how important buses are for their communities and local economies".
He insisted councils are "desperate to protect them" despite suffering huge funding cuts.
The CBT and the LGA want local authorities to be given more freedom to improve networks through the Bus Services Bill, which is going through Parliament.
Ms Etkind said local authorities need to have "the full range of powers at their disposal".
The Government has suffered a series of defeats in the Lords over the legislation, including on its bid to prevent councils forming companies to provide bus services.
Transport Secretary Chris Grayling has said the Bill does not seek to allow councils to retake control of the bus market.
Instead, he wants private companies to "dominate" it via "improved partnerships or franchising" - in which services are specified and operators can bid for them.
The plan is similar to the system currently operated in the capital by Transport for London.
A Department of Transport spokesman said: "Buses are vital for local communities, connecting people, homes and businesses, and we are giving councils extra powers to work in partnership with bus companies to improve the service passengers expect and deserve.
"While decisions on funding for services are a matter for local authorities, we provide around £250 million to support bus services every year, benefiting people up and down the country."Subscribe to our Newsletter