Public services such as libraries should serve the whole of a population, not just 'most' of it. Photograph: Don McPhee

The future of Britain's libraries is a subject that has been quietly - and not so quietly - debated in bookish milieux such as this for several months, even years.

Judith Flanders suggested that paying for libraries might be a productive route forward, Private Eye has been flagging up how increasing management and computer costs have reduced the spend on books. Others, such as Tim Coates, the Bookseller, and Richard Charkin are all either campaigning for, or commenting on, the need to address the dire status of what should be a valuable cultural resource. But it was a sentence, quoted by Rachel Cooke in the Observer, which made me most determined to join the fray. Yinnon Ezra (head of leisure services at Hampshire County Council, the third biggest library service in the country) stated that "We have to ask whether fiction should remain in libraries when most people buy books."

There is an incredible assumption here that "most people" have the means to pay for reading matter, similar to arguing, as I often think the government does, that "most people" can afford private health care, so why bother supporting the NHS? Who are "most people"? And where do they live? My guess is that the "most" to which Ezra is referring are metropolitan types, like me, like the readers of the Guardian and this blog, the sort who probably do spend a couple of hours and £20 every few weeks on reading material. But like the NHS, libraries aren't, or shouldn't be, exclusively aiming for the people who could afford to survive without them. The clue is in the name: public services. Such services are meant to serve the whole of a population, not just "most" of it.

And I think if Ezra actually considered, as those in the book business do on a daily basis, how many people buy fiction, and read it, the numbers would prove surprising. "Most" people do not have the disposable income to spend on books. A National Poverty Hearing in 2006 run by Oxfam cites that one in four adults in the UK and one in three children live in poverty. Those figures rather undermine Ezra's stance.

But what most astounds me about this position is that Ezra seems to forget that some of the key users of libraries are those who very rarely buy anything: children. If he were to cast his mind back to his own childhood, he might remember that some of those who benefit most from libraries are those who as yet can't argue for keeping them. I spent nearly every Saturday afternoon of my childhood choosing three or four plastic-wrapped hardbacks from our local library; buying books was a special treat for birthdays or Christmas. And I don't think this has changed for most. Children love stories, and, if they're lucky enough to have been well-taught, love reading. Only the middle classes can really afford to own all the books that a child will listen to, and read, throughout his or her education. Harry Potter was sold at a great discount (£8.87 in my local supermarket) but even one book a week at that price would result in an annual bill of £461.62. And picture books for the very young are not much cheaper.

Of course it's not just children who are affected by a reduction in book-buying and library services. Every unemployed person looking for a job, every new immigrant in need of information about English classes, every pensioner wanting company, loses out if libraries are considered surplus to the requirements of the many. The further impoverishment of the more vulnerable sectors of our society affects us all.

Those of us who are in a position to voice our concerns about this need to do so, whether it's by getting involved with campaigns or simply finding our libraries and supporting them. I recently found out, for example, that some libraries will accept second-hand books in good condition for their stocks. I usually give mine to charity, but since libraries are apparently being treated like charities now, then, obviously, they need donations.

Because it seems unlikely that the government will help. Margaret Hodge, the new culture minister, was recently interviewed in The Bookseller. She said that she has no plans "to ringfence book spending" because "I would not want government to determine where there should be libraries". In fact she plans to do very little: "What I can do is just act as an advocate." A bit like Ezra's "most", that "just" speaks volumes. British libraries don't need another voice of support on the sidelines; they need saving from the centre. Nobody can afford to lose them, least of all a government that assures us of its devotion to education.