Percival was respected for the time he had spent as a Japanese prisoner of war. Serving as life president of the Far East Prisoners of War Association (FEPOW), he pushed for compensation for his fellow captives, eventually helping to obtain a token £5 million of frozen Japanese assets for this cause. This was distributed by the FEPOW Welfare Trust, on which Percival served as Chairman. He led protests against the film "The Bridge on the River Kwai" when it was released in 1957, obtaining the addition of an on-screen statement that the movie was a work of fiction. He also worked as President of the Hertfordshire British Red Cross and was made an Officer of the Venerable Order of Saint John in 1964.