Duchess of Cambridge photos: St James's Palace turns up the heat

Prince William and Kate in the Solomon Islands yesterday. Legal action on their behalf will start today (Getty Images)

International lawyers acting for the Royal Family have been told they should be "prepared to go the whole way" in efforts to prevent the publication of topless photographs of the Duchess of Cambridge in countries around the world.

Last night, St James's Palace confirmed that the royal couple would be making a criminal complaint against the photographer or photographers responsible for taking the pictures. French prosecutors must then decide whether or not to pursue charges.

As the Duke and Duchess near the end of their nine-day Diamond Jubilee year tour of the Far East and Pacific today, their legal representatives will be in a court in Paris to seek compensation for the publication of the photos, which they will argue broke French civil law on personal privacy.

Harbottle & Lewis, a London-based commercial law firm, is instructing a team of Paris-based advocates who will seek an injunction from French authorities to prevent further publication of the photographs that have so far appeared in the French magazine Closer and in the Irish Daily Star.

The images of the Duchess sunbathing topless, which were taken at a French chateau owned by Viscount Linley, are already easily available across the internet.

This, coupled with the fact that the scale of damages in France is likely to be very small compared with the legal muscle the Palace is preparing to deploy, means that the entire exercise is being seen, according to one senior royal source, "as Prince William and Kate trying to draw a line in the sand, not for today, but for tomorrow".

The court action against the French edition of Closer is essentially the opening legal salvo of a longer campaign to ensure that the Duchess's life does not mirror that of Diana, Princess of Wales.

Clarence House has said it will review each hurdle as it comes. When asked if Italian lawyers would swing into action if Chi magazine publishes a promised 26-page special featuring the photographs today, Clarence House said it was "early days". However, The Independent understands that Harbottle & Lewis has made provisional contact with legal associates in Rome and in New York.

Both Closer in France and Chi in Italy are owned by the former Italian Prime Minister, Silvio Berlusconi.

Diplomatic sources in the UK said it was unlikely that any pressure would be put on Mr Berlusconi to intervene.

An Italian media source said: "Mr Berlusconi does not know what is published inside the Mondadori group of magazines he owns, nor indeed what is being shown on his television channels. He is far too busy trying to keep himself out of jail." It is expected that further efforts will be made this week to offer the pictures at a discounted rate to publications in the US and Australia, as well as German tabloid magazines.

The full folio contains about 200 pictures taken about half a mile from the Chateau D'Autet in Provence.