Queen Elizabeth II is meditating. Swathed in white fur and with her eyes closed, she seems momentarily far from the heavy responsibilities she carries.

This intimate portrait, a hologram by photographer Chris Levine, is one of 60 pictures of the British monarch on show at London's National Portrait Gallery from Thursday to mark her diamond jubilee.

From stiff official portraits to her defaced image on an infamous record sleeve by punk rockers the Sex Pistols, the exhibition explores many facets of a queen who, after six decades on the throne, is still something of a mystery.

"The queen remains a fascinating character, an enigma," said Paul Moorhouse, curator of The Queen: Art and Image, which has come to the capital following a tour of Britain.

"These are questioning images," he told AFP. "Some of these pictures really ask: Do we need a queen? And what is she for?"

From the 1960s, snapshots of the queen at breakfast with her family or sifting through paperwork with her private secretary began to appear alongside the traditional portraits of her in full regalia.

This portrayal of her as a working woman and a mother marked a radical departure from previous monarchs who maintained a distance between themselves and their subjects.

As one image from 1968 recalls, the queen even invited television cameras to film a fly-on-the-wall documentary about the royals a decision she reportedly later regretted.

"I think the decision to shed the regal image and try to become more ordinary, more down to earth, was a risky move," said Moorhouse.

"When you become more informal, contempt can creep in - and that's actually what happened."

By 1977 the Sex Pistols had dared to black out the queen's eyes and mouth on the cover of their single God Save the Queen, which was banned by the BBC for comparing the British monarchy to a "fascist regime".

"The Sex Pistols image actually desecrates the image of the queen," said Moorhouse. "That still creates a lot of controversy, even now."

Several photographs explore the major crises suffered by the family over the following two decades, which saw, among other setbacks, the divorce of three of the queen's four children.

A grainy image captures her shock as, garbed in a raincoat, she inspects the wreckage of her Windsor Castle residence following a devastating fire in 1992.

Another shows the queen and her husband, the Duke of Edinburgh, standing at the gates of Buckingham Palace, among huge piles of flowers left in homage to Princess Diana after her death in a car crash in Paris in 1997.

Their grim faces recall the huge plunge in public support for the monarchy following the queen's initial refusal to speak publicly about the death of her former daughter-in-law.

Since then, said Moorhouse, "she has regained the affection and the respect of the nation" - but works from the last decade suggest contemporary artists felt free to let their views on the monarchy be known.

Agence France-Presse