The Nation's Mantelpiece, by Jonathan Conlin

It's a story with a broad sweep, but too many details are brushed over

For anyone who believes that free admission and public access to national galleries and museums are a New Labourite obsession, the history of the National Gallery is a corrective. From its establishment in London in 1824, public access was paramount. It was founded on the faith that all Britons could be stakeholders in a priceless collection of art, regardless of class or education.

In The Nation's Mantelpiece: A History of the National Gallery, Jonathan Conlin recounts how, within three decades, visitor numbers had passed one million. In 1910, the fifth Marquess of Lansdowne decided to sell his Rembrandt, The Mill. The gallery, offered first refusal, could not match the £100,000 price, but people flocked to see it before it went overseas.

So the gallery's popularity is not new. Nor are battles with the government over funding and admission charges, as much of Conlin's comprehensive account makes clear. In the years leading up to the First World War, some MPs argued against awarding a purchase grant because of the costs of rearmament and the ongoing war in Afghanistan.

While the threat of better-funded rivals rings alarm bells today, there were warnings more than a century ago that Americans were pricing the gallery out of the market. In 1909-1910, £1m of art was sold from the UK to the US. Dealers offered to save works in return for peerages.

The book is packed with fascinating incidents, such as a suffragette's slashing of Velazquez's the "Rokeby Venus", and Victorians' gin-fuelled picnics in the galleries. There are disputes over taste; in the early 20th century, Impressionists were viewed with suspicion.

But alongside the glorious trivia, there are frustrating moments when incidents are alluded to without explanation, and the narrative lacks clarity. The Prince of Wales's description of a proposed extension as a "carbuncle" is mentioned twice before his comments are cited. This was indeed "famous", but it was also 22 years ago. Equally irritating are references to alleged over-cleaning of works without any assessment of whether permanent damage resulted.

Both Neil MacGregor, the former director, and Charles Saumarez Smith, the sitting boss, offer laudatory quotes in support of the book. It is an achievement, but, without an insider's knowledge, the experience is less satisfying than might be hoped. The 260 illustrations are lovely, though, and an indisputable reminder of the gallery's glory.