John Collin (18 October 1928 – 25 February 1987) was a British actor frequently seen on UK television during the 1960s and 1970s, mainly in supporting roles such as ITC's The Saint (S5/E21). Collin's best-known role was as Detective Sergeant Cecil Haggar in the long running BBC police series Z-Cars. Another notable role was as Guardian officer Tom Weston in the 1971 ITV political fantasy The Guardians. He also played Mr. Alderson, the father-in-law of James Herriot, in both the 1975 film All Creatures Great and Small and the later BBC TV series television series. (Via Wikipedia)