Hugh Detmar Torrens O'Neill, 3rd Baron Rathcavan (14 June 1939 â 11 November 2025), was a British hereditary peer and businessman who sat as a crossbencher in the House of Lords from 1994 until 1999.
O'Neill was educated at Eton College. He ran Lamont, a textile company in Northern Ireland, in the 1980s and was chairman of the Northern Ireland Tourist Board before taking on the Brasserie St Quentin in Knightsbridge in 2002. Lord Rathcavan died on 11 November 2025, at the age of 86.