THE new Senior British Trade Commissioner in Hongkong is to be Mr Francis Cornish, the head of the Foreign Office's news department, according to a source in London. The Foreign Office yesterday declined to comment on the report, but an official said Mr Cornish was due for a move. He would replace Mr Stephen Day, who has resigned due to health reasons. The senior trade commissioner is London's top diplomat in the territory, and is expected to become Britain's first Consul-General to Hongkong after 1997. Mr Cornish works closely with Foreign Secretary Mr Douglas Hurd, and has accompanied him on several trips to Hongkong. He also works with Mr Gus O'Donnell, Prime Minister Mr John Major's press secretary. Mr Cornish, 49, joined the Foreign Office in 1968 after six years as an army officer. He served in Kuala Lumpur from 1970-71, followed by two years in Jakarta, and three years as a first secretary at the Foreign Office in London. Mr Cornish was posted to the British Embassy in Bonn in 1976, before serving as assistant private secretary to the Prince of Wales from 1980-83. He was then posted to Brunei as high commissioner, and moved to Washington in 1986 as an information counsellor, before assuming his present post.