Campaigners will be challenging the government and Crown Estate over questions raised by the imminent move of William and Kate to a new home in Windsor Great Park.

The property belongs to the Crown Estate, which has the job of raising funds for the government.

Campaign group Republic is to challenge the claim the move will not cost the taxpayer, while raising questions about the relationship between the Crown Estate and the royals.

Speaking today, Graham Smith said:

"Why does the Crown Estate allow the royals to pick and choose which properties they can use, and where is the evidence that they are paying market rates for Forest Lodge?"

"These are public properties, the public has a right to know what is paid for their use. And why has the Crown Estate evicted two families so William can move house?"

"While reports claim the costs will be met by the couple, it is likely to cost the taxpayers hundreds of thousands of pounds to upgrade the home's security infrastructure."

"Meanwhile the taxpayer continues to fund a 20-room four-storey mansion for William and Kate inside Kensington Palace. Why? How many homes does he need?"

"I will be writing to the Crown Estate and ministers challenging them over the royal use of public property and the arrangements between royals and the Crown Estate."

William and Kate have four homes:

A mansion inside Kensington Palace, complete with 20 rooms, 4 storeys, several "reception rooms" and "drawing rooms," lots of staff bedrooms, a gym, an elevator, and a walled garden.

Anmer Hall on the grounds of Sandringham, a ten bedroom mansion with swimming pool and tennis courts.

Tam-Na-Ghar, a large house on the Balmoral estate.

Forest Lodge, an eight bedroom mansion in Windsor Great Park.

They are moving to the lodge from the four bedroom Adelaide Cottage just down the road.