While posting my notes on my reference back for Labour Conference I fell back on the OBR statistic that Brexit had cost the UK 4% of GDP. I thought a chart would have been helpful and so went looking for one.
The NIESR published an article, Revisiting the effects of Brexit, which now they’ve archived it, no longer has the chart they made from the model, but google search can still find it today.
Their model tries to disentangle the effects of the COVID slump, and the article, dated 2023, says,
These estimates suggest that Brexit had already reduced UK real GDP relative to the baseline by just under one per cent in 2020 as consumers and businesses adapted their expectations even before the TCA came into force. Our estimates further suggest that three years after the transition period, UK real GDP is some 2-3 per cent lower due to Brexit, compared to a scenario where the United Kingdom retained EU membership.