
On This Day...
20th April
Channels
1964
BBC Two was expected to launch at 7.20pm. However, a serious power failure at Battersea Power Station knocked out the power supply to BBC Television Centre.
BBC One was kept on the air via facilities at Alexandra Palace.
Other than occasional news updates on BBC Two that evening, where presenter Gerald Priestland explained the power issues, no other programmes were broadcast on BBC Two that day.
The first official programme on BBC Two was Play School at 11am the next day.
1964
BBC TV is renamed BBC One, following the launch of BBC Two.
The channel's on-screen identity is updated with the introduction of a new globe symbol (the second globe device).
2009
BBC Parliament's on-screen presentation is updated to bring it into line with the core BBC TV News branding, first seen a year earlier.
Both packages were produced by Lambie-Nairn.
Programmes
1957
The final episode of The Adventures of Sir Lancelot airs on ITV.
1957
The final episode of The Appleyards airs on BBC TV.
1960
The first episode of The Love of Mike airs on ITV.
Sitcom. Starring Michael Mediwn.
1961
The first edition of Spotlight at 6 airs on BBC One South West.
10-minute regional news programme presented by Tom Salmon.
1964
The earliest edition of Blue Peter to exist in the BBC archives, featuring Chris Trace, with guest presenter Sandra "Sandy" Michaels and regular contributor George Cansdale.
1964
The first edition of Newsroom airs on BBC Two.
Presented by Gerald Priestland. The programme is broadcast from Alexandra Palace due to a power cut, which disrupted the official launch (of the programme and channel) from TV Centre.
Richard Baker, from Alexandra Palace, linked together programmes for BBC One.
Newsroom introduced the idea of "in-depth reporting" and the presenters were taken from the reporting staff.
The programme had a more informal presentation style, with presenters wearing pullovers, in contrast to the suits worn by newsreaders on BBC One.
1968
The final episode of US series The Monkees airs on BBC One.
1970
The first episode of For the Love of Ada airs on ITV.
1970
The first edition of Words and Pictures airs on BBC One.
Presented by actor Gabriel Woolf.
The new series was previewed in Out of School on 31st March 1970 at 1.55pm on BBC One.
1975
The first edition of Winner Takes All airs on ITV. Quiz show hosted by Jimmy Tarbuck.
1979
The final episode of Flambards airs on ITV.
1984
20 Years Ago Today... airs on BBC Two.
Ludovic Kennedy narrates a celebration for BBC Two's 20th anniversary.
1988
The first episode of An Ocean Apart airs on BBC One.
1990
The first episode of The Chief airs on ITV.
1990
The first episode of Bangkok Hilton airs on BBC One.
An award-winning three-part film drama. About a young Australian woman's search for her father.
Starring Nicole Kidman and Denholm Elliott.
1991
The final episode of Davro airs on ITV.
1991
The final edition of The Little and Large Show airs on BBC One.
1994
The first episode of US series Frasier airs on Channel 4.
1994
The final episode of Luv airs on BBC One.
Comedy series. By Carla Lane. Starring Michael Angelis and Sue Johnston.
1998
The final edition of The Time...The Place... airs on ITV.
2001
The final edition of Right to Reply airs on Channel 4.
2015
The first edition of Alex Polizzi: Chefs on Trial airs on BBC Two.
2015
The first edition of Decimate airs on BBC Two.
Quiz. Presented by Shane Ritchie.
2015
The first episode of Safe House airs on ITV.
Crime drama. Set in the Lake District. Starring Christopher Eccleston, Paterson Joseph, Jason Merrells and Marsha Thomason.
2016
The final edition of Secret Britain airs on BBC One.
Documentary. Presented by Ellie Harrison, Chris Hollins and Denise Lewis.
2018
The 5,000th episode of Hollyoaks airs on Channel 4.
2022
The final episode of The Thief, His Wife and the Canoe airs on ITV.
Drama. Based on the true-life story of canoe man John Darwin and his wife Anne. Written by Chris Lang.
Starring Eddie Marsan and Monica Dolan.
Test Cards
1964
BBC Test Card D is introduced.
The design was intended for use on the 405-line VHF system.
1964
BBC Test Card E is introduced.
The design was intended for use on the 625-line UHF system, used by BBC Two.
Reports regarding the length of service of this design vary - some claim it was withdrawn after only one day, others say it remained in use for about a month.
Its replacement was a modified version of Test Card C, which remained in use until 1967, when Test Card F came along.

On This Day...
20th April
Births
1938
TV news presenter,
Peter Snow.
1939
Former TV announcer,
Edward Cole.
1945
TV chef/announcer/presenter,
Patrick Anthony.
1946
Actor and TV presenter, Ben Bazell.
1961
Actor and former TV presenter,
Nicholas Lyndhurst.
1969
TV presenter,
Chris Jarvis.
1974
TV presenter,
Sean Fletcher.
1976
TV news presenter,
Becky Jago.
Events
1989
John Leslie presents
Blue Peter (BBC One) for the first time.
1990
Andy Crane presents the links between the programmes in the CBBC 'broom cupboard' for the final time.
Research for On This Day in TV History is by Paul R. Jackson.
Details about test card/teletext in-vision music and BBC trade test films are available as a result of decades of research and logging by members of the Test Card Circle.