It is hard to calculate the current cost of Brexit, because there is no obvious counterfactual. The original version of this column, first published in November 2017, calculated the cost by letting a matching algorithm determine which combination of comparison economies best resembles the pre-referendum growth path of the UK economy. The results suggested a loss of 1.3% of GDP, or close to £300 million per week, since the vote took place. Subsequent updates using the latest OECD data suggest that the negative drag from the Brexit vote now appears to be roughly £350 million a week, but under current OECD forecasts we can expect the output loss to increase to about 4% of GDP by end-2020.
Benjamin Born, Gernot Müller, Moritz Schularick, Petr Sedláček