Andrew Motion, the former poet laureate, has dismissed suggestions from consultancy KPMG that libraries are "not very much used" and should be run by volunteers as foolhardy, outlandish and potentially catastrophic.

A new report from KPMG into public sector reform says that "giving councils total freedom on libraries could mean that they create huge social value from engaging a community in running its own library, backed up with some modern technology, whilst also saving large amounts of money on over-skilled paid staff, poor use of space and unnecessary stock".

Speaking on the Today programme earlier this week, one of the report's authors, Alan Downey, said that although "libraries are hugely important in the national psyche ... there is a problem with libraries, that they are not very much used and very expensive to run".

"We're not suggesting in this report that libraries should be closed down, we are saying that libraries and other community facilities might be better off if they're run by [a] community that values them rather than by the state," he said.

But Motion, who is chair of the Museums, Libraries and Archives Council, said that if the government were to take up the report's suggestions, it would "harm the most disadvantaged" in the UK. He stressed that maintaining libraries was fundamentally important.

"Of course money must be saved, and it will be saved, in the public library sector, but to put the whole thing at risk is absolutely the wrong step to take," said the former poet laureate. "Good libraries, like good anythings, need expert people working within them. Maybe there is a role for some aspect of volunteering but all the central stuff must be done by people who are qualified to do it ... I think it would be a catastrophe."

"Whether we are traditionalists about libraries or not, and I consider myself not, we ought to be able to accept that libraries are very important pieces of machinery for delivering to human beings what they need – information, pleasure, instruction, enlightenment, new direction in life. They're also joining up with services which help people with difficulty reading, and working with people learning English – to put all that in danger is exactly the wrong thing to do," he said.

Although Motion "completely accept[ed]" that this is a time "when we ought to be able to have a grown-up conversation about how things can be done differently", he felt that "simply not to recognise what libraries fundamentally are, and what their potential is, as this report seems to do, is frustrating, in the view of all the work that has been done and the manifest values of these things".

Motion said he hoped the government wouldn't "waste too much time" debating the "more outlandish suggestions" floated in the report "when there is a very challenging task ahead to deliver relevant, quality library services with less money".

"There is no harm in society periodically asking itself which services should be publicly funded, and how they should be run, but it is a foolhardy notion that a modern economy would wantonly abandon resources that support learning and help build our potential as human beings," he said. "We are at a critical time. A time for big thinking, not big mistakes that would set the country back and harm the most disadvantaged who need the best possible libraries and free access to books."