Buckingham Palace gallery completes Classical makeover

Next week, as part of the Golden Jubilee Celebrations, the Queen's Gallery will reopen to the public after a four-year closure with an exhibition of royal treasures – paintings, sculpture, furniture, ceramics and much else from 13 royal palaces.

The old Queen's Gallery, behind Buckingham Palace, was an awkward, inflexible and nondescript place. Built originally as a conservatory by John Nash, it was converted into a chapel, and then bombed during the war. It was the Queen's idea to refurbish it as a gallery in 1962. The opening times were always puzzling though – it would shut its doors between temporary exhibitions.

Now it has had a dramatic makeover by John Simpson, a neo-classicising architect whom John Nash himself would have approved of. The result is a gallery which has all the virtues and vices associated with restraint, tradition, respectability and a modicum of opulence.

A huge, lumpish, Doric portico has been added to the entrance to prevent visitors getting wet. A fanfare of a long entrance hall leads up to a double staircase flanked at the top by a bevy of green marble columns with Ionic capitals.

Marble? I flick a columns with my finger. It has a metallic ring to it. Ah, no, Jonathan Marsden tells me, curator of decorative arts, not marble but scagliola, a kind of plaster which, when veneered, looks like marble. "It features a lot in the interior of Buckingham Palace..." he adds.

In fact, the whole gallery, now tripled in size, and stocked as it is with clocks, paintings, sculpture and huge desks looks a bit like the interior of Buckingham Palace – just as the Hermitage Museum in Somerset House looks like a wing of the Hermitage in St Petersburg.

The opening exhibition is a culling of treasures from the royal palaces, 450 items from an estimated total collection of half-a-million artefacts – I make that 0.1 per cent. Two interesting questions hang in the air: Were the royals discerning collectors? And why, if this exhibition purports to be a gathering of the greatest objects acquired, is it not greater still? Because there is no denying that its collection of paintings, for example, does not begin to compare in range and quality with the royal collections at the Prado in Madrid.

A massive equestrian portrait of Charles I by Van Dyck dominates one gallery. Charles I was our most discerning royal connoisseur, a skill he picked up at the Spanish court, and most of the masterpieces from his collection are now in the Prado because Cromwell organised a sale of them to pay off his debts.

So when we look at this portrait we feel sad for the loss of all those works by Titian, Raphael and Correggio that might have been here. Still, this is no time to weep. There are many compensatory joys – including an enigmatic Vermeer not in the recent National Gallery show and, perhaps best of all, the drawings galleries where we can shrug off the atmosphere of cloying respectability and stare in wonder at Michelangelos and Leonardos.