Formally at present a P5 nation cannot be forced to surrender P5 status. However reality matters in realpolitik.
Practically the situation over the last 70-years-or-so has been one of progressive accumulating changes in the relative strengths of the P5 nations. What has not happened (except once, see below*) is a rapid reduction in strength.
At inception there was not a link to nuclear weapons status, indeed the USA was the only country with nukes at the time. However there was a very clear de facto understanding that these were the significant Allied military powers to be reckoned with in the decades to come.https://en.wikipedia.org/wiki/Permanent ... ty_Council
* The one reduction in power that did happen was in 1949-1971 when the Kuomintang retreated to Taiwan, and then in 1971 the UN de-recognised Taiwan and recognised the PRC mainland. It is actually worth reading through the wiki entry on this in some detail. In essence the P5 seat move reflected the way in which the (Chinese) nation had been broken up and then reconstituted, and the subsequent shift in power.https://en.wikipedia.org/wiki/United_Na ... ution_2758
This actually creates a precedent I would suggest as derecognition of the UK could occur, as a recognition of reality (even if the UK tried to argue that a U of England and the principality of Wales counted it would be somewhat laughable). That would take away the UK's seat. Then individual ex-UK nations could reapply to become UN members, but in doing so would not necessarily obtain a P5 seat. Given that other nations are quite keen to obtain a P5/6/etc seat (that veto power is a powerful tool, desired by many) you could imagine this would be a feast with many knives and one menu item. I rather suspect that the circumstances of a rump-England at such a moment would be so dire as to preclude much in the way of a successful English rearguard action. Emergence of a P6 with Brazil and India entering P-status is my most likely scenario outcome. There are many others.
You have only to look at the ongoing saga of Chagos islanders and the recent UN Gen Ass resolution to appreciate that the UK (or England) could find the world a pretty unfriendly and lonely place, if there is red meat to be shared around.https://www.un.org/press/en/2019/ga12146.doc.htmhttps://en.wikipedia.org/wiki/Expulsion ... CJ_hearing
Up for grabs in the red meat department:
- A P5 veto & seat
- Cyprus SBA
- forcing the (English) to divest of nukes
- forcing the City into a untenable situation
- etc, etc, etc