Gideon's tie: stripe on knot/no stripe on knot. Handkerchief: square/ pointed / very visible / almost invisible.
Before giving evidence in court Gideon swears the oath. At the end he adds 'So help me God'. These words are not used in the UK.
The background scene of London outside Gideon's office windows is actually a miniature set rather than back projected film. This is revealed by the fact that the cars and buses crossing the bridge are clearly small models or toys. In fact in the opening shot of Gideon looking out of his office at night, the miniature is used on its own instead of inserting stock footage, and the model vehicles are particularly noticeable.
Simon's surname is credited as Farnaby Green, despite the dialogue explicitly stating that it should be the hyphenated Farnaby-Green.
Mrs. Sparrow orders a "Half and Half" to chase her large gin. This is also known in some parts as a "Black and Tan", where a dark beer is layered on top of a pale beer - such as Guiness stout on top of Bass pale ale. However, the beer Mrs. Sparrow is given is all one color.
However, a "Half and Half" refers to a number of different drinks, depending on location and, whereas it may be a "Black and Tan" in Ireland, comprising Guinness and lager or ale, this movie is set in London where it is more likely to be a mixture of mild and bitter which are much closer to the same mid-brown colour.
The casserole dish is removed from the oven with a cloth as it's obviously hot and is steaming yet less than a minute later, the daughter removed the lid with her bare hand without burning herself.
At his office in Scotland Yard Gideon borrows matches to light his pipe and hands them back. Goes out on a call to see a lady at some flats. She asks for a light for her cigarette and Gideon take a box out of his pocket.