Season 1 BBC One , 1973 Season 2 BBC One , 1974 Season 3 BBC One , 1975 Season 4 BBC One , 1975 Season 5 BBC One , 1976 Season 6 BBC One , 1977 Season 7 BBC One , 1978 Season 8 BBC One , 1978 - 1979 Season 9 BBC One , 1979 Season 10 BBC One , 1979 - 1980 Season 11 BBC One , 1980 Season 12 BBC One , 1980 - 1981 Season 13 BBC One , 1981 Season 14 BBC One , 1981 Season 15 BBC One , 1982 Season 16 BBC One , 1982 Season 17 BBC One , 1983 Season 18 BBC One , 1983 - 1984 Season 19 BBC One , 1984 Season 20 BBC One , 1984 - 1985 Season 21 BBC One , 1985 Season 22 BBC One , 1985 Season 23 BBC One , 1986 Season 42 BBC One , 1995
, 1973