1 of 12
This kangaroo cartoon image helped launch BBC Two in 1964.

2 of 12
BBC Two developed a reputation for eye-catching idents over the years - like this which appeared in between programmes in 1975.

3 of 12
But the "2" figure developed in the early 1990s and quickly became a favourite with viewers.

4 of 12
It was used in various ways to promote specific shows, such as comedy or wildlife strands.

5 of 12
The swan-like shape of the number "2" was used to create the cygnets in this image.

6 of 12
Snooker has long been a part of BBC Two's line-up.

7 of 12
This early 90s Christmas tree logo featured flashing red bulbs to spell out the number.

8 of 12
By the mid 90s, the logos were becoming more sophisticated.

9 of 12
Several different commissions are made for each BBC Two season.

10 of 12
The logos often relate to changes in season.

11 of 12
Many of them have a simple yet eye-catching concept - here the logo takes the guise of an electric fly trap.

12 of 12
The most recent animations use up-to-the-minute animation techniques.