A formal UK Constitution doesn't exist and is a striking example of this

https://en.m.wikipedia.org/wiki/Constitution_of_the_United_K...

The constitution of the United Kingdom comprises the written and unwritten arrangements that establish the United Kingdom of Great Britain and Northern Ireland as a political body. Unlike in most countries, no official attempt has been made to codify such arrangements into a single document, thus it is known as an uncodified constitution. This enables the constitution to be easily changed as no provisions are formally entrenched.

In the US we only have a remnant of that in the Senate, in what has been popularly marketed as "the Nuclear Option." A Senator just makes a point of order that a Senate rule is the opposite of what it actually, verifiably is. The chair denies it, the Senator appeals the decision, and a majority of the Senate then overrules the chair.

After this has happened, the rule just changes and whatever was not in order in the past is in order in the future (or vice versa.) In the Senate as in Parliament; the majority of Parliament is the law, it can't break the law.