The economy is provably performing less well than it would have done if we remained in the EU. By every metric.
How can it be provable? A UK still in the EU (after Covid/Ukraine/Trump's tariffs...) does not exist. From the Julian Jessop link up thread;
The NBER paper assumed any underperformance must have been due to Brexit...
The paper essentially uses two approaches. One is to compare the performance of the UK to some average of a very large group of other economies with whom it may have little in common.
The other approach is to leave the judgement entirely to a computer programme. Synthetic control models use an algorithm to find the weighted group of countries (or ‘doppelgänger’) whose performance was closest to that of the UK before Brexit. This control group can be a very odd bunch. Indeed, here are the weights in the NBER doppelgänger: US 61.4%, Estonia 10.9%, Greece 9.5%, Italy 6.7%, Ireland 4.4%, Latvia 3.4%, Iceland 3.0% and Hungary 0.7%.
None of these are obvious benchmarks for the UK. Where, in particular, are Germany and France?
More fundamentally, the best fit in one period and in one set of circumstances may not be the best in another, especially where there have been many shocks (not just Brexit) which could be expected to hit the UK differently from other countries (notably Covid and the energy crisis).
I have therefore done my own version of the NBER chart. This confirms that the real outlier over this period was the US. In per capita GDP terms, the UK has marginally underperformed France and marginally outperformed Germany, which are more obvious benchmarks.
When U.K. farmers raised concerns about Australian imports
How would British farmers feel about the EU's Mercosur trade deal?
Jan 2026
Thousands of Irish farmers protest against EU-Mercosur trade deal.
https://www.theguardian.com/world/2026/jan/10/thousands-of-irish-farmers-protest-against-eu-mercosur-trade-deal