For three years, the Prince and Princess of Wales have brought their children up at Adelaide Cottage, a peaceful refuge in the grounds of Windsor Castle.
But the cosy, four-bedroom house, which is relatively modest by royal standards, was never going to be the 'forever home' for William, Kate, Princes George and Louis and Princess Charlotte.
Royal sources have told The Mail on Sunday that the prince and princess are considering upsizing to a grander residence.
One option, according to sources, could be Fort Belvedere, a magnificent gothic-revival mansion nestled in a hidden corner of Windsor Great Park.
Built in the 18th century, Fort Belvedere became the favourite home of Edward VIII, who lived there before he became monarch and after he abdicated to marry Wallis Simpson.
In fact, it was there that he signed the papers which sealed his infamous abdication in 1936.
The sprawling, grade II-listed property is set in 59 acres of grounds and has an outdoor swimming pool and tennis court, which sources say is particularly appealing for Kate and Charlotte, both of whom are enthusiasts.
Known as The Fort, the country house also features a rose garden, walled garden, kitchen garden, large greenhouse, stables, two lakes, paddocks and three cottages for staff.
Several cannons used in the Jacobite rising used to be positioned along its battlements.
One well-connected source told the MoS: 'They feel they have outgrown Adelaide Cottage and need somewhere more substantial.
'This is the perfect new home for them. It has a swimming pool and tennis court, and Charlotte loves playing tennis.'
The MoS understands that although the royal couple are considering their options, no move is imminent.
William and Kate, both 43, have previously been linked with a potential move to Royal Lodge, the 30-room mansion in Windsor where Prince Andrew lives, but Andrew resisted pressure from the King to leave.
This newspaper has learnt that an alternative plan involved the prince and princess and their family moving into a wing of Windsor Castle.
However, that is also understood to no longer be viable.
The couple moved from Kensington Palace in west London to Adelaide Cottage in August 2022, along with George, 12, Charlotte, ten, and Louis, seven.
The property is a ten-minute walk from Windsor Castle and a short drive from Lambrook School, which is attended by the three children.
Their move coincided with a challenging period for the Royal Family, with Queen Elizabeth dying at Balmoral Castle only weeks later.
Adelaide Cottage also provided a private and tranquil setting for Kate's recovery from chemotherapy after she was diagnosed with cancer last year.
Insiders say a move to a more substantial property would mark a new chapter for their family.
The couple are weighing up which senior school to choose for Prince George, with Eton, where fees are more than £63,000 a year, believed to be the front-runner.
William and Kate are said to put a high value on privacy and a rural setting – two requirements they would continue to maintain if they were to move to The Fort.
Edward VIII rescued the building, which was used as a summer tea house by Queen Victoria, from falling into decay and installed a swimming pool, tennis court and even a Turkish bath.
In the two decades after he left, the property remained largely empty until 1956, when Queen Elizabeth's cousin Gerald Lascelles moved in.
Originally a mansion with 30 to 40 rooms, he is believed to have reduced it to an eight-bedroom house.
It was leased to Canadian retail billionaire Galen Weston and his wife Hilary in the early 1980s.
The Westons built a polo stud in the grounds and hosted Queen Elizabeth, Prince Philip and Princess Caroline of Monaco for Hilary's 60th birthday party in a huge marquee next the house.
Mr Weston, who was said to be worth £5.2 billion, died at 80 in 2021, but his family continued to live at the property, which is owned by the Crown Estate.
