1885 Hex Map of London
dice.camp
dice.camp
Fun fact: Officially, there is no such place as "London". ;)
No Londoner would write 'the City' to mean anything other than 'the City of London' (i.e. excluding the rest of the 'city') - which makes it unclear to me how to read your comment, especially given other familiarity/information. Are you saying 'nobody' (I'm not being pedantic on that, hence quotes) living/working in the City sees it as anything other than another borough? (But implicitly others do?)
I think it's down to how one interprets the question. Some might see the question as: "Where did London start/expand out from" and other "If I were to look at London now, where is the center of where you would consider London".
https://access.bl.uk/item/pdf/lsidyv3c0c937d
"Taking the City of London for the central division, round it we have grouped six similar divisions ; these, in their turn, being encircled by a group of twelve hexagonals. We have chosen St. Paul's Cathedral as the core, because there we have not only the highest ground and the most familiar object, but the acknowledged central postal, telegraphic, and telephonic district of the universal system. Should it be objected that Charing Cross— or even Victoria, the centre of Greater London— would suit as well, it is scarcely necessary to point out that until the conditions of the two localities are reversed, and Commercial London loses its importance, the suggestion must fail."
The book itself is worth a read. Each hexagon could be divided in six, it says (of course). Then each 6th into 16 triangles with sides a "48th of a superficial mile ... about twice the length of Waterloo Bridge and contain, say, 200 lamps each". He goes on to say each lamp could be adorned with these mapping notes as an "ocular demonstration" for travellers. An 1885 Google Maps.
> Fun fact: Officially, there is no such place as "London". ;)
London, Ontario officially exists.
Here's a Post Office map of London from 1857: https://mapco.net/kelly1857/kelly.htm
As you can see, it covers a much larger area than just the City.
19th century writers -- e.g. Austen, Trollope, Doyle -- use "London" to mean the metropolis as a whole, not just the City.
And Apsley House, built in the 1770s, was for years popularly known as "No. 1, London", because it was the first house you passed after going through the toll-gates at Knightsbridge (at the western edge of Westminster).
Errr, yes there is. The City of London officially exists. The London postal district officially exists. The Greater London administrative area officially exists.