More than 180 UK council-run libraries have closed or been handed over to volunteer groups since 2016, new data shows.

Freedom of information requests sent by the BBC to every UK library authority, along with Arts Council England data, found that around 950 libraries – a third of those remaining – reduced their hours in the past eight years. Two thousand jobs have been lost, and dozens more possible closures over the next year were identified.

The most deprived communities – identified using the government’s indices of multiple deprivation – were around four times more likely to lose a library than the richest.

The data confirms “what we have long suspected”, said Isobel Hunter, chief executive of Libraries Connected, the charity representing library services in England, Wales and Northern Ireland. “Libraries are hit hardest in the very areas that need them most.”

Former children’s laureate Michael Rosen, speaking on BBC Breakfast on Tuesday morning, said that he feels a “mixture of horror and sadness” at the closures. “It’s a soft target, isn’t it? If you close libraries, nobody dies – that’s what they think. But what’s happening is it’s society who suffers and people who suffer.”

Much of the value of libraries is “preventative”, said Hunter, and so investing in them brings “huge” returns for communities and taxpayers. Libraries provide support with employment, literacy, health and digital skills, which “reduces the need for more expensive interventions later on”.

Birmingham city council, which effectively declared bankruptcy last year, recently ran a public consultation on proposed plans to reduce the number of its libraries from 35 to 25.

“Ministers must urgently fix local government finances so that councils are funded at a level which sustains a properly resourced, staffed and supported library service in every part of the country,” Hunter said.

Louis Coiffait-Gunn, CEO of the Chartered Institute of Library and Information Professionals, said that the organisation is “deeply concerned but not surprised” about the loss of 2,000 library roles. There is a “worrying trend of de-professionalising the public library workforce”.

“Library volunteers need to be recognised and thanked, but a volunteer’s role should only ever be to augment professional and trained staff, they can’t replace them without a negative impact on service,” he added. Community-run libraries are a “sticking plaster”, reliant on “enough local people always being able to afford the time and money to volunteer”.

A government spokesperson said that libraries “play an important role in communities by providing spaces for people from all walks of life to access books, work and learn”.

“We recognise the pressures they face, and are committed to giving stability back to local councils so services such as these can best meet the needs of their communities,” they added.