Question: What English television presenter originally hosted the British television and radio talent show Opportunity Knocks?

full_context: Document 1: Stuart Hall (presenter): James Stuart Hall (born 25 December 1929) is an English former radio and television presenter. He presented regional news programmes for the BBC in North West England in the 1960s and 1970s, while becoming known nationally for presenting "It's a Knockout" and "Jeux Sans Frontières". His later career mainly involved football reporting on BBC radio.
Document 2: Britain's Got Talent: Britain's Got Talent (often shortened to BGT) is a British television talent show competition, and is part of the "Got Talent" franchise. Produced by both Thames (formerly Talkback Thames) and Syco Entertainment production, and distributed by FremantleMedia, it has been broadcast on ITV since June 2007, and is hosted by Ant & Dec, with each series accompanied by a sister show on ITV2 entitled Britain's Got More Talent. Contestants of any any age, who possess some sort of talent, can audition for the show, with their performance judged by a panel of judges; the current lineup consists of the show's creator Simon Cowell, Amanda Holden, Alesha Dixon, and David Walliams. Those that make it through the auditions, compete against other acts in a series of live semi-finals, with the winning two acts of each semi-final proceeding into the show's live final. The prize for winning the contest is a cash prize (the amount varying over the show's history), and an opportunity to perform at the Royal Variety Performance in front of members of the British Royal Family, including either Queen Elizabeth II or the Prince of Wales. To date, the show has had eleven winners, ranging from musicians and singers, to variety acts, magicians and dancers.
Document 3: Opportunity Knocks (UK TV series): Opportunity Knocks is a British television and radio talent show originally hosted by Hughie Green, with a late-1980s revival hosted by Bob Monkhouse, and later by previous winner Les Dawson.
Document 4: Hugh Downs: Hugh Malcolm Downs (born February 14, 1921) is a retired long-time American broadcaster, television host, news anchor, TV producer, author, game show host, and music composer. He is perhaps best known for his roles as co-host of the NBC News program "Today" from 1962–71, host of the "Concentration" game show from 1958–69, and anchor of the ABC News magazine "20/20" from 1978–99. He also served as announcer/sidekick for "Tonight Starring Jack Paar", host of the PBS talk show "Over Easy", and co-host of the syndicated talk show "Not for Women Only".
Document 5: The Bob Monkhouse Hour: The Bob Monkhouse Hour was a British televised variety show from 1958 which was fronted by the comedian Bob Monkhouse, and featured musical stars of the day, contemporary comedians, and various other variety acts.
Document 6: Celebrity Squares: Celebrity Squares is a British comedy game show based on the American comedy game show "Hollywood Squares". It first ran from 20 July 1975 to 7 July 1979 and was hosted by Bob Monkhouse, then from 8 January 1993 to 3 January 1997 and was also hosted by Monkhouse.
Document 7: Dave Hughes: David William "Hughesy" Hughes (born 26 November 1970 in Warrnambool, Victoria) is an Australian stand-up comedian, and a radio and television presenter.
Document 8: Nigel Green: Nigel McGown Green (15 October 192415 May 1972) was a South African-born English character actor. Because of his strapping build & commanding height, [6ft 1 inch] & regimental demeanour he would often be found playing military types and men of action in such classic sixties films as "Jason and the Argonauts", "Zulu", "Tobruk" and "The Ipcress File".
Document 9: Millican &amp; Nesbitt: Millican & Nesbitt are a British vocal duo, comprising Alan Millican and Tom Nesbitt. They were former miners from Northumberland, England, who won the UK television talent contest, "Opportunity Knocks", in 1973. They went on to release two charting singles and three albums. Millican & Nesbitt appeared on the final version of "Opportunity Knocks" hosted by Hughie Green in 1978.
Document 10: Mike Doyle (comedian): Mike Doyle is a British comedian, vocalist and broadcaster from Carmarthen, Wales, but is now based in nearby Bridgend. Doyle made his debut television back in 1988, winning the BBC One talent show "Opportunity Knocks".
Document 11: Hugh Paddick: Hugh William Paddick (22 August 1915 – 9 November 2000) was an English actor, whose most notable role was in the 1960s BBC radio show "Round the Horne", in sketches such as "Charles and Fiona" (as Charles) and "Julian and Sandy" (as Julian). Both he and Kenneth Williams are largely responsible for introducing the underground language polari to the British public.
Document 12: Bob Monkhouse: Robert Alan "Bob" Monkhouse, OBE (1 June 1928 – 29 December 2003) was an English entertainer and comedian.
Document 13: Double Your Money: Double Your Money is a British quiz show hosted by Hughie Green. Originally broadcast on Radio Luxembourg, it transferred to ITV in 1955, a few days after the commercial channel began broadcasting. It was produced by Associated-Rediffusion until 1964 and then by Rediffusion London, and it finished in 1968 when the company lost its franchise. There were 260 thirty-minute episodes.
Document 14: Alan Freeman: Alan Leslie "Fluff" Freeman, MBE (6 July 1927 – 27 November 2006) was an Australian-born British disc jockey and radio personality in the United Kingdom for 40 years, best known for presenting "Pick of the Pops "from 1961 to 2000.
Document 15: Hughie Green: Hugh Hughes Green (2 February 1920 – 3 May 1997) was an English television presenter.
ground_truth: Hugh Hughes Green