The Diamond Queen, By Andrew Marr

It would be a foolhardy critic who badmouths a royal paean this weekend, but the woman described as having "shrewd judgement" and being "a wicked mimic" deserves a better assessment of her six decades on the throne than this po-faced hagiography.

Andrew Marr nails his Royal Standard to the mast in his preface: "Britain without her would have been a greyer, shriller, more meagre place." So much for objectivity. Marr lambasts his erstwhile republicanism: "This was mainly because I thought it would make me feel clever."

Unfortunately, the reverse does not apply. His ardent defence of Elizabeth II is glib and incurious. Stuffed with PR spiel ("Britannia... travelled a total of 1,087,623 nautical miles calling at over 600 ports in 135 countries"), it rarely goes beyond the glossy surface of the royal story.

In the 20 pages devoted to George V, we inevitably learn that he was "over-enthusiastic about his world-class stamp collection" but not how he financed this obsession. Princess Elizabeth's "Grandpa England" sold the unequalled royal collection of Gillray and Rowlandson cartoons (acquired by the far more cultured George IV) to the US Library of Congress.

Touching on honours, Marr ignores the devaluing of knighthoods by a seedy choir of pop stars, but extols the OM and gives a glowing list including "Henry Moore, Lucian Freud and Anthony Caro". How odd that he fails to mention royal art acquisitions in the past century. As a visit to Buckingham Palace gallery reveals, the Royal Collection pretty much ended with Victoria.

In other areas, there is excessive padding. Even though he admits the affair is "trivial", Marr devotes five pages to the attempt of Tony Benn as Postmaster General to remove the Queen's head from stamps.

Marr's observation that following the death of the Queen Mother "some Palace people thought that... the Queen came to feel liberated" is a rare exception to the pervading blandness. This shallow, unrevealing portrait ends with Marr trilling like a toadying 18th-century poet laureate: "The British public's view of the Diamond Queen is sparkling, crystal, clear." One can almost hear the "wicked mimicry" this will inspire in Buckingham Palace.