The City of London (aka the Square Mile) is literally a world unto itself. Even the Mayor of London is not the mayor of the City of London.
Haven't read it for a while but I do recall the word "strange" appearing a lot.
> The mayor is scrutinised by the London Assembly and, supported by their Mayoral Cabinet, directs the entirety of London, including the City of London (for which there is also the Lord Mayor of the City of London)
https://en.wikipedia.org/wiki/Mayor_of_London
> In 1965 the county was abolished and replaced by Greater London, a two-tier administrative area governed by the Greater London Council, thirty-two London boroughs, and the City of London Corporation.
Think of it as a vertical, focused embassy