Why the Queen wants to build on her rural retreat The houses would be part-built by the families themselves to help keep costs down. "The Prince's Foundation for Building Community is delighted to be working with residents of Ballater, the Balmoral Estate, the Cairngorms National Park Authority and other interested parties to explore a pilot project relating to self-build housing," Dittmar confirms. A spokesman for the Cairngorms National Park Authority says discussions are "at an early stage." Cameron and his wife, Samantha, spent the weekend at Balmoral last month as guests of the Queen and the Duke of Edinburgh. The 49,000-acre Deeside estate was bought by Queen Victoria and Prince Albert in 1848 and it has remained the Scottish retreat of the Royal family. The Queen gave Prince Charles exclusive use of Birkhall after the death of Queen Elizabeth, the Queen Mother in 2002. He and the Duchess of Cornwall spend much of the year at the house, which was the venue for their honeymoon in 2005. The Prince is known for holding strong views on the merits of traditional architecture and has been involved in several pioneering housing projects. The best known is Poundbury, the estate on land owned by the Duchy of Cornwall on the outskirts of Dorchester, in Dorset. Poundbury was built to a traditional high-density urban pattern, rather than a suburban one, and focused on creating an integrated community of shops, businesses, and private and social housing. A Buckingham Palace spokesman says: "A consultation process has begun regarding provision of low-cost housing in the Ballater area and discussions are at a very early stage."