Indeed, this is spun nonsense. The problem with the UK right now is brexit. You can see it on a GDP graph: https://www.macrotrends.net/global-metrics/countries/GBR/uni...

It's growing steadily through the 60's-2000's, has a notable dip[1] at the 2008 financial crisis, then starts growing again until just about 2015. And it's been flat since.

The UK had found a profitable niche as the transatlantic hub of finance and commerce, and threw it out the window in a fit of nativist pique over the wrong languages being spoken on street corners.

[1] More pronounced than comparable nations, to be fair. The UK was always more dependent on finance.