UK autumn statement: How much is Brexit to blame for the budget 'black hole'?

"Around half of the fiscal hole, and the political instability that comes with that, is down to Brexit," John Springford of the Centre for European Reform said on Twitter in October, in an exchange on the relationship of the UK's EU membership to its economic performance.

In a CER report in June, he commented on a £29 billion (€33.2 billion) package of tax rises announced earlier in the year by Rishi Sunak, then finance minister -- up "to their highest share of GDP since the 1960s", he said.

"These tax rises would not have been needed if the UK had stayed in the EU (or in the single market and customs union)," Springford argued.