Cambridge University Library, which turned 75 in October last year, is probably the ugliest building in Cambridge, but those of us who regularly use it love it very much. To us, its undeniable ugliness is as irrelevant as the warts on the face of a beloved mother. It may have fewer early-printed books than the British Library, and fewer literary manuscripts than the Bodleian in Oxford, but it is far better run than either. Readers are allowed to search for their books in the stacks, which does not mean that the entire collection is mis-shelved – only that you have a better chance of ending up with the book you're looking for than in either of the other institutions. For those of us who have the right to enjoy it, the library is heaven on earth.  The building was designed by Giles Gilbert Scott in the rationalist-fascist style of the mid-1930s. Its most conspicuous feature is a blunt tower, visible for many miles – even from the M11 – making it a far more significant identifier of Cambridge than King's College Chapel (though you won't find the tower on too many tea towels). It stands 12 storeys high; the rest of the original library stands at six. As the tower often has a plume of steam emerging from it, the whole structure has the air of a place where books are burned rather than read. The building is built around two internal courtyards, like prison yards, which cannot be accessed from outside; the entrance facade stands atop an intimidating flight of stairs.  Whatever else you say about the library, you must confess that it is bold. But this boldness is now being vitiated by endless rather ordinary accretions. The least impressive of these was unveiled last September, and consists of 14 bollards that block off the approach to the library steps. Although this seems in part intended as a means of reducing parking space, it is an installation: 1% of the library's budget has to be spent on public art (as outlined in the Per Cent for Art scheme, monitored by Arts Council England).  The bollards are bronze, in the form of columnar piles of books. Imagine the library built like a fortress to safeguard our intellectual inheritance, and outside it piles of apparently rejected books. The idea is not so much shocking as humiliatingly naff. Ten of the columns are fixed, but in four the individual books can be made to rotate. If you line them up right, you get the words "Ex Libris", the name of the sculpture, which according to the artist (a local man, Harry Gray) is "a metaphor for the library itself; you can't just look at the books, you have to use them to gain understanding, to get the bigger picture". Gray appears not to know that Ex Libris is also the name of the best-known purveyors of electronic library resources, now guaranteed free advertising in perpetuity.  The money for the bronze book bollards was provided by the Arcadia Fund, run by the academic and philanthropist Lisbet Rausing and her husband Peter Baldwin. Altogether the fund has provided the library with $980,000 (£612,000), intended "to create new programmes and services, particularly for undergraduates, and also improve the external environment of the ­ library". But if you are contemplating some bronze bollards of your own, don't approach the fund, which does not consider unsolicited applications. Instead, it invites applications on the suggestion of its advisory board, which includes the vice-chancellor of Cambridge University.  The new librarian, Anne Jarvis, took office in April last year and cannot be blamed for the bollards. Still, she has taken it upon herself to defend them against their critics, saying that it was she who wanted to bring "the library out beyond its walls and create a welcoming space". As anyone who has tried to smoke a cigarette or eat a sandwich in that space could tell you, it is usually in shadow, draughty and cold much of the year. All they had to do to create a welcoming outside space would have been to rip up the tarmac and make a sheltered garden, at a fraction of the price.  Jarvis's next proposal is to sell the library's name to anyone who is vainglorious enough to pay for it. The CUL already includes libraries named for other benefactors; Jarvis now seeks an over-arching donor, who will out-donate all the others. Could the CUL become the Coca Cola Library, or the Barclays Library? Would there be anything members of the university could do to prevent it?
It may have been ugly, but Cambridge University Library was heaven on earth before someone decided to improve it, writes Germaine Greer