Almost all royals learned to swim in the secret pool at Buckingham Palace. As a cost-saving measure, King Charles III has downregulated the water temperature of the pool.
Staff have always been allowed to use the pool, but only if they adhere to certain regulations. If an employee shows up, he has to stay in the pool unless he is invited to stay, writes royal author Brian Hoey in "Not In The Cis Of Life Of The Royal Curtains": The Royal Secrets Of Life.