Season
- Season 0 1966-12-25
- Season 1 1964-02-04
- Season 2 1965-01-06
- Season 3 1966-01-02
- Season 4 1967-01-17
- Season 5 1968-01-02
- Season 6 1969-01-02
- Season 7 1970-01-05
- Season 8 1971-01-04
- Season 9 1972-01-03
- Season 10 1973-01-04
- Season 11 1974-01-07
- Season 12 1975-01-20
- Season 13 1976-01-05
- Season 14 1977-01-07
- Season 15 1978-01-06
- Season 16 1979-02-26
- Season 17 1980-01-14
- Season 18 1981-01-05
- Season 19 1982-01-11
- Season 20 1983-01-10
- Season 21 1984-01-09
- Season 22 1985-01-07
- Season 23 1986-01-06
- Season 24 1987-01-05
- Season 25 1988-01-04
- Season 26 1989-01-09
- Season 27 1990-01-08
- Season 28 1991-01-07
- Season 29 1992-01-06
- Season 30 1993-01-04
- Season 31 1994-01-10
- Season 32 1995-01-09
- Season 33 1996-01-08
- Season 34 1997-02-27
- Season 35 1998-02-19
- Season 36 1999-01-28
- Season 37 2000-01-12
- Season 38 2001-01-25
- Season 39 2002-01-10
- Season 40 2003-01-09
- Season 41 2004-01-08
- Season 42 2005-01-13
- Season 43 2006-01-12
- Season 44 2007-03-13
- Season 45 2008-01-15
- Season 46 2009-01-26
- Season 47 2009-10-13
- Season 48 2010-09-27
- Season 49 2011-08-08
- Season 50 2012-07-23
- Season 51 2013-08-12
- Season 52 2014-08-18
- Season 53 2016-03-16
- Season 54 2017-01-19
- Season 55 2018-02-05
- Season 56 2019-01-23
- Season 57 2020-01-16
- Season 58 2021-01-04
- Season 59 2022-03-31
- Season 60 2024-07-22
- Season 61 2025-08-18
Season 61 Episode
- Season 21 The Intelligence Man
- Season 21 Microworld!
- Season 21 A New Green Revolution?
- Season 21 Spies in the Wires
- Season 21 Valley of the Inca
- Season 21 The Conquest of Parasites
- Season 21 Reflections on a River
- Season 21 A Normal Face
- Season 21 Prisoners of Incest
- Season 21 Signs of the Apes, Songs of the Whales
- Season 21 Professor Bonner and the Slime Moulds
- Season 21 The Mind of a Murderer: The Case of the Hillside Strangler
- Season 21 The Mind of a Murderer: The Mask of Madness
- Season 21 A Cruel Inheritance
- Season 21 The Malvern Link
- Season 21 Contented Cows and Other Animals
- Season 21 Picking Winners
- Season 21 The Brain Puzzle
- Season 21 Global Village
- Season 21 Ivan
- Season 21 A Mathematical Mystery Tour
- Season 21 Supercharged
Horizon - Season 21 Episode 1 The Intelligence Man
7.40 60 minutes Sir Cyril Burt died in 1971, the most eminent psychologist of his age. Within two years the most bitter and disturbing scientific controversy since Piltdown Man saw Burt accused of lifelong faking and manipulation of phoney data. How and why was Burt allowed to get away with this?
