The publication of topless pictures of the Duchess of Cambridge were condemned as being like the worst excesses of the paparazzi during the Diana, Princess of Wales era, St James's Palace said today.

Lawyers are being consulted by royal aides after the images showing the future Queen wearing just a pair of bikini bottoms while sunbathing were published in the French magazine Closer.

William and Kate are said to be feeling "anger and disbelief" at the publication of the photographs, taken while on a private holiday.

In a strongly worded statement St James's Palace said: "Their Royal Highnesses have been hugely saddened to learn that a French publication and a photographer have invaded their privacy in such a grotesque and totally unjustifiable manner.

"The incident is reminiscent of the worst excesses of the press and paparazzi during the life of Diana, Princess of Wales, and all the more upsetting to the Duke and Duchess for being so.

"Their Royal Highnesses had every expectation of privacy in the remote house. It is unthinkable that anyone should take such photographs, let alone publish them."

William and Kate are midway through a Diamond Jubilee tour of the Far East, which had been going well but is likely to be overshadowed by the publication of the images.

They were taken last week while the couple were staying in Provence at a chateau owned by Lord Linley, the Queen's nephew.

St James's Palace said the royal couple would not let the controversy distract them.

A spokesman said: "The Duke and Duchess remain focused currently on their tour of Singapore, Malaysia, Solomon Islands and Tuvalu on behalf of HM the Queen."

A source added: "Their sadness has turned to anger and disbelief as we learn more about the photographs.

"They can't believe the pictures were taken, they can't believe anyone would publish them. The level of intrusiveness means a red line has been crossed."

The pictures are likely to reignite the controversy over privacy which raged around Prince Harry last month, when images emerged of him naked in a Las Vegas hotel.

Staying in a £5000-a-night hotel suite, Harry was filmed wearing a hat, sunglasses and colourful swimming shorts, and socialising with bikini-clad women at a pool party.

The Sun was the only British newspaper to defy a royal request issued via the Press Complaints Commission not to publish the photos of Harry in the nude with an unnamed woman.