The Duke and Duchess of Cambridge are said to be "saddened" by claims made by a French magazine that it will publish topless photographs of Kate.

The royal couple broke new ground by touring a mosque for the first time during their tour of Malaysia, but all media attention was on speculation that another member of the Royal Family will be at the centre of embarrassing images.

Closer magazine said it has exclusive pictures of Kate topless on the terrace of a guest house, taken during a brief holiday she enjoyed with William in France last week.

The couple were staying in Provence at a chateau owned by Lord Linley, the Queen's nephew, ahead of their Diamond Jubilee tour of south-east Asia and the South Pacific on behalf of the Queen.

St James's Palace declined to comment on the claims made by the publication, but royal officials said that if the photos are genuine and are published, it would be like "turning the clock back 15 years", according to reports.

The magazine's French website showed an image of its new front cover with a heavily pixellated image of a woman with dark hair, it claims is the Duchess, in a bikini apparently about to remove her top.

William and Kate were told about the allegations before they visited they Assyakirin Mosque and had also looked at the images on the website. Speaking about the royal couple a source said: "They're saddened their privacy has been breached - if it has been breached."

The source stressed it could not confirm if the pictures were of Kate as they appeared to have been taken with a long lens and were pixellated. The source added: "We will talk to our lawyers in London and counterparts in Paris to see what options are available... We're not aware of anyone (in the UK) seeking to publish so the Press Complaints Commission is not coming into it."

The BBC's royal reporter Nicholas Witchell said it appeared British newspapers were offered the alleged photographs of the couple last week, but turned them down.

The Duke and Duchess arrived in Singapore on Tuesday and are currently in Malaysia before travelling on to Borneo then the South Pacific. Malaysia is a largely Muslim country with laws on public decency which makes the timing even more difficult.