The UK government is famous for strange and hard to understand protective marking systems.
The Government Protective Marking Scheme (GPMS) gave way to the Government Security Classification (GSC) in 2013.
At first blush, the reduction from six classifications to just three seemed like a good move. But they added caveats and handling instructions and sub-classifications, so that the OFFICIAL tier actually dissolved into a series of winces, shrugs and head-scratching when considering applicable security controls.
In honour of the tenth anniversary of the introduction of the GSC (which, by the way, some government departments and arms length bodies have still not implemented), I present to you the Protective Marking Bingo Generator.