I wonder what the Brits get in exchange for their giving up of personal freedoms?
Some stagnation is to be expected from high energy prices and trade disruption (brexit).
British surveillance state tolerance has always been pretty high for Europe, and is typically "sold" to the average citizen as anti-crime.
In the UK, you have leaders who are incredibly unpopular, they have no real skills, and they spend most of their time pandering to very small groups of people for various reasons. There is no real incentive to do anything relevant to voters, in fact you have seen over the last five years that political engagement has dropped significantly in a way that has generally benefitted incumbents.
To say this another way: the point of the UK system is so that people who are manifestly unfit to govern end up governing, and a small rotating group of special interests are continually pandered to (there is complete blindness to this in the UK, people often assume this is wealthy people when wealthy people are largely ignored...a politics grad working in research for a think tank will have more power in actual government than someone who gives £10m to the governing party).
Almost all the wealth is in the South East of England. Outside of that the country is much poorer.
I drive from Manchester to Dorset once a month to visit my parents. There is a clear line where I notice all the street signs, the service stations, roads etc are better kept. Cars and houses are in better condition/news.
Purchasing power adjustment is ~1.5 (in favor of China, obviously), so this should not be close no matter how you slice it.
e.g. Jobs in London (even remote ones) will pay twice as much as jobs in the North West of England.
From what I can tell the prosperity gap is also large enough that small errors don't really matter; I already looked at urban china vs average UK (systematically favoring China) and the numbers are still not close (something like $30k vs >$40k even after PP adjustment).
Using the Median as far as I am concerned is meaningless as the South/South-East skews everything. It is quite obvious as you drive across the country. You can see it with your own eyes.
I don't really care that much about the comparison with China.