The media has been warned to keep clear of the Duke and Duchess of Cambridge while they are at their Norfolk home.
Letters have been sent out by Kate and William’s communications secretary calling for “acts of harassment and breaches of privacy to cease”.
The letters, distributed by Norfolk Police and signed by the Cambridges’ communications secretary, say the couple have “a more than reasonable expectation of privacy”.
It called for “acts of harassment and breaches of privacy to cease”.
The letter went on: “There have in the past been a number of intrusions into the privacy of the Royal Family which in the main have been as a result of professional photographers using long-distance lenses, not only to observe the Royal Family, but also to photograph them going about their activities on the estate.”
Earlier cautions to photographers meant “the position has greatly improved”, the letter said.
But, it continued: “However, we would remind you again of the position. The Sandringham Estate trusts that there will not be a need to take any further action other than bringing these points to your attention.”
William and Kate will spend the next few weeks in the country house that was given to them by the Queen.
William has two weeks’ paternity leave from his job as an air ambulance helicopter pilot and will join his wife and George in getting to know the latest member of their family.
The 10-bedroom secluded red brick mansion is a short drive from Sandringham House itself and is where the couple are thought to want to spend much of their time while their children are young.
They recently spent around £1.5m on renovations so that the house not only has a new roof, swimming pool and tennis court but also a new kitchen, garden room and nursery, as well as separate accommodation for the children’s nanny.