The percentage of graduates who receive a First (First Class Honours) has grown from 7% in 1997 to 26% in 2017 ...
First Class Honours (1st, 1 or I) – typically 70% or higher
Second Class Honours;
Upper division (2:1, 2i or II-1) – typically 60–69%
Lower division (2:2, 2ii or II-2) – typically 50–59%
Third Class Honours (3rd, 3 or III) – typically 40–49%
Students who do not achieve honours may be awarded an ordinary degree, sometimes known as a 'pass'. ...
The upper division is commonly abbreviated to '2:1" or 'II.i' (pronounced two-one). The 2:1 is a minimum requirement for entry to many postgraduate courses in the UK.
https://en.wikipedia.org/wiki/British_undergr...