We see many combination of custom number plates on a day to day basis however in many countries the law behind number plates sometimes restricts certain combinations being put on for sale. The main reason for this is simply because they may cause offense to other road users.
This combination was one of those to be removed from sale in the UK. The combination reads Drunk in the format of 'DR12UNK' as the 1 + 2 together is meant to look like an 'R' in the world of custom number plates.
Many combinations are banned from sale around the world due to the possibility of other road users being offended by what they read. To prevent this from happening, they are restricted from being put on for sale to ensure all combinations on the road that are sold are not offensive.