BBC Two

1964–1967
On 21 April 1964, the launch of the channel was delayed by an infamous power failure in Central London the day before.

1967–1974
On 2 July 1967, the first official colour channel in the UK launched on UHF and with it came a brand new ident.

1991–1997
As part of an extensive rebrand to cast off BBC2's "highbrow" tone on 16 February 1991, Lambie-Nairn launched a brand new set of idents, featuring a numeral '2', which originally lasted for 10 years until they were replaced in 2001.

1997–2001
The 1991 ident package was retained following the corporate rebrand of the BBC in 4 October 1997 with a new logo and new idents commissioned.

2001–2007
Throughout November 2001, the logo was slightly modified, being stacked and placed inside a purple box. The idents were changed for the first time in 10 years; the "2" symbol stayed the same, but it was given a pair of arms and a "personality". The BBC added to the roster of 4 idents over the years.

2007–present
A new logo was introduced on 18 February 2007, with the typography on the word "TWO" being changed from the Gill Sans typeface to the Avenir typeface, and the box's colour changing violet to teal. The blade "2" has been slightly altered for this look.

2015–present
The boxless variant of the 2007 BBC Two logo has been used on the revived 1991 idents in Northern Ireland from 1 January 2015. On 27 September 2018, BBC Two launched a new look, uses the boxless 2007 logo and ditched its famous "2" icon that has been in use since 1991. The box logo from 2007 is currently used as a primary logo and the "2" symbol resembles a curved wave.

1991–2007, 2014–2018
Used from 16 February 1991 to 18 February 2007. From 2001 to 2007, the 1991 2's replaced the white 2, and the few idents had robotic arms. To celebrate its 50th birthday in 2014, BBC Two brought back many old idents, including the 1991-97 and 1997-2001 set of idents featuring the "2". In 2015, the 1991-2001 set of idents and stings were brought back on a more permanent basis.

2007–2018
On 18 February 2007, the 1991 "2" symbol was slightly redrawn. From 2015, it was used only on promos end-boards until 26 September 2018. No longer used on the BBC Two website.

2018–present
A simplification of the '2' as seen in the idents and other on-air presentation elements has been used since 27 September 2018.