In the early prison visit scene, the chair and table combo isn't screwed down. In reality this would be a high security issue.
Hugh Laurie's ministerial car is shown as having a private registration. Ministerial cars retain their original registration. Royal cars have private registrations. Diplomatic cars have registrations that follow a different format.
In the end credits, for the information used under licence, the word "information" is misspelled as "imformation".