The King accused the Church of England of being “corrupted by loathsome political correctness”, a newly uncovered letter reveals.

Written in 1998 while he was Prince of Wales, Charles said that as he grew older he was more drawn to the “timeless traditions” of the Greek Orthodox Church.

He added: “They are the only ones that have not been corrupted by loathsome political correctness.” The King, 75, whose father was Greek Orthodox until he became Anglican on his marriage to the then Queen, has forged strong links with the Eastern church, which focuses on traditional sacrament and scripture rather than preaching and prayer.

In the past 20 years, some have accused the CofE – of which Charles is now head – of putting political correctness ahead of Christian values. In the same letter, Charles also criticises genetically modified crops.

It was written to royal interior designer Dudley Poplak, who died in 2005, and was among six sold for £1,700 at Lay’s Auctions in Penzance, Cornwall. A spokesman said: “It’s an intriguing letter. Royals aren’t supposed to make political remarks in public but these were in private correspondence.”

Meanwhile, the King has leased part of his Sandringham Estate in Norfolk to Environment Bank, a private company which will restore wetlands, meadows and ancient forest. The bank has a collection of UK sites that developers fund to offset environmental harm from their projects.

It emerged this week King Charles and Queen Camilla enjoyed a secret spa break after their demanding trip to Australia and Samoa. The couple broke up the arduous journey back from the South Pacific island of Samoa by heading to India, where they enjoyed several days at the Soukya resort known for its wellness programmes and Ayurvedic treatments.

A raft of celebrities are known to have stayed at the £3,000-a-week resort near Bangalore including Oscar winner Emma Thompson and Archbishop Desmond Tutu. The spa location is understood to be well-known to Charles and Camilla with them both having visited several times before. In fact, Camilla is also understood spent a few days at the resort earlier this month too, prior to heading to Australia for the start of the tour.