4 January – The world record-breaking long-running comedy seriesLast of the Summer Wine starts as a 30-minute pilot on BBC1's Comedy Playhouse show. The first series run starts on 12 November and the programme runs for 37 years until August 2010.
6 January – Sesame Street, goes to air on UTV, the first time the series is transmitted on television in Northern Ireland.
14 March – Sitcom Are You Being Served?, set in a department store, begins its first regular series on BBC1, six months after the pilot episode had been broadcast as part of the Comedy Playhouse strand. It becomes one of the longest-running BBC comedy shows and goes on to spawn a 1977 British feature film and the spin-off series Grace & Favour which begins in 1992.
25 March – The pilot episode of sitcom Open All Hours, set in a corner shop, airs as part of Ronnie Barker's series Seven of One on BBC1.
March – Experimental Ceefax teletext transmissions begin.
April
1 April – Ronnie Barker stars in "Prisoner and Escort", the pilot episode of Porridge, airing as part of Seven of One on BBC1.
18 April – ITV London begin showing the American horror series Night Gallery, created and hosted by Rod Serling.
30 April – Children's science fiction drama The Tomorrow People is shown for the first time on ITV.
18 May – ITV London show the network premiere of the cult British horror film Witchfinder General, starring Vincent Price and Ian Ogilvy. The film is later shown on ITV Midlands and ITV Anglia on 23 November and 10 December.
6 August – James Beck, who stars as Private Walker in the BBC sitcom Dad's Army, dies of a burst pancreas at the age of 44. Although the series continues until 1977, the part of Walker is not recast and the show carries on without him.
10 September – The Goodies makes its debut in Zambia on ZBS.
24 September – BBC1Leslie Phillips sitcom Casanova '73 is moved at short notice to a later timeslot because of its risqué content; Mastermind (which has just started its second series) replaces it in the earlier slot on 27 September, helping the quiz to become a hit.[4]
26 September – Scottish and Grampian show live coverage of a Scotland home football international for the first time when they broadcast the World Cup qualifier between Scotland and Czechoslovakia.[5]
17 October – ITV shows a home England football international live from Wembley for the first time when it broadcasts the World Cup qualifier between England v Poland.[6]
The sixth series of the BBC sitcom Dad's Army opens with the episode "The Deadly Attachment" containing the "Don't tell him, Pike!" exchange which becomes rated as one of the top three greatest comedy moments of British television.[7]
23 November – 10th anniversary of the first episode of Doctor Who
28 November – The Dad's Army episode "The Honourable Man" shown that night is the last full one featuring actor James Beck due to his death during the series recording (he features in prerecorded portions of the last series episode, "Things That Go Bump in the Night", shown on 5 December). His character, Private Walker, is subsequently written out of the series.
17 December – The government announces severe measures to reduce electricity consumption due to the ongoing overtime ban by the National Union of Mineworkers, strike action in the electricity supply industry and effects of the 1973 oil crisis. Part of these measures are that both BBC and ITV television are ordered to end their broadcasting day earlier than usual, at around 10:30pm in order to save energy. The early closedowns commence that day and continue until Sunday 23 December. They are then lifted so that Christmas and New Year programming can air as normal and provide some light relief to the public. The restrictions will be reimposed from Monday 7 January 1974 and remain for a further month.[8]