Don't bother engaging me in a discussion about the usefulness or otherwise of GDP and GNI because the tiny details make no difference to my point.
Examine the nine EU neighbours and near-neighbours across NW Europe. These are the countries we have most in common with. How does our income per head compare?
Well the average wealth generated per person is measured using GDP or GNI per capita by various methods and these are all available on the World Bank website.
So take both GDP and GNI measures and take a Purchasing Power Parity version and another version, giving a range of different approaches and average them to compare the UK with its EU neighbours. (It's not a flawless method but the answer doesn't come out much different whatever way you try to do this.)
They are on average 20% better off than us. The major exception is France which, as the other unreformed post-imperial wreck, repeatedly fights us for bottom place.
20%. Yes, a fifth.
That's like removing full VAT from everything.
If we abandon our post-imperial neuroses, stay in the EU, abandon the twentieth century class war for a more effective political creed, and participate fully in the European project, then we can be 20% richer. Maybe more, if we miraculously become clever enough to take proper advantage of our many economic advantages.
It sounds good to me. How does it sound to you?