Not 100% reliable? It's not reliable at all.
The graph you shared only serves to show how the value of paper/digital currency has become detached from the value of finite assets over time, and bears no relationship whatsoever to the trends in overall productivity or purchasing power of everyday goods and services.
What's more, the trend in that graph would be pretty much identical for all other advanced economies as well. So using that as a stick to beat the UK with is just absurd and suggests that, once again, you've just re-posted something you've seen elsewhere that fits your narrative without actually bothering to understand it properly.