The Lost Prince is a British television drama about the life of Prince John – youngest child of Britain's King George V and Queen Mary – who died at the age of 13 in 1919. John had epileptic seizures and an autism-like developmental disorder, and the Royal Family tried to shelter him from public view; the script did not present the Royal Family as unsympathetic, instead showing how much this cost them emotionally (particularly John's mother, Queen Mary). Poliakoff explores the story of John, his relationship with his family and brother Prince George, the political events going on at the time (such as the fall of the House of Romanov in 1917) and the love and devotion of his nanny, Charlotte Bill (Lalla).

A Talkback Thames production written and directed by Stephen Poliakoff, it was originally broadcast in January 2003. It won three Emmy Awards in 2005.