[dane-pgp]

That's a great explanation, but it's also worth adding that the City of London was the only city mentioned[0] in Magna Carta, which stated:

"the City of London shall have all its ancient liberties by land as well as by water"

These liberties being "ancient" even in 1215 AD means they date back to "time immemorial"[1] (that is, before 1189 AD) and thus their exact nature is not known. As such, replacing the legal basis for the City would likely have contravened or at least complicated the interpretation of that foundational document.

[0] https://www.cityoflondon.gov.uk/things-to-do/history-and-her...

[1] https://en.wikipedia.org/wiki/Time_immemorial#English_and_Am...

[pmyteh]

Yes - the traditional liberties of the City are long-standing and fought for. I'm not sure that being mentioned by name in Magna Carta was reason enough to leave it unreformed. The Cinque Ports have been reduced to essentially ceremonial status despite their mention (and the large majority of Magna Carta has simply been repealed over the years[0] - it's not a constitutional document in the sense that it's ever been entrenched).

[0]: https://www.legislation.gov.uk/aep/Edw1cc1929/25/9