Brexit dealt the UK economy a "productivity penalty" of £29billion, or £1,000 per household, according to a Bank of England policymaker.
Jonathan Haskel, an external member of the Bank's monetary policy committee, claimed that a wave of investment "stopped in its tracks" in 2016 following the vote.
He added that the UK had"suffered much more of a productivity slowdown than other large economies because of Brexit.
The Treasury told the BBC it did not recognise Mr Haskel's figures.
The Bank declined to comment.
Mr Haskel was asked in an interview why he thought the UK was an "extreme outlier" when it came to facing a slowdown in productivity.
Back to Brexit
He said: "We suffered much more. A bit of that is that we have this larger financial sector. But I think it really goes back to Brexit.
"Investment just plateaued from 2016, and we dropped to the bottom of G7 countries."
Since the Brexit referendum in 2016, there has been a global pandemic, swiftly followed by an energy crisis, which has made estimating any financial impact directly related to Brexit difficult.
Some economists, including at the International Monetary Fund, have suggested that uncertainty surrounding Brexit, including the unsettled issue of the Northern Ireland Protocol, has deterred at least some spending.
Mr Haskel referred to a calculation to show what the UK economy could have looked like if investment had carried on growing at the rate it had been before the referendum, compared to what it is currently growing at.
He described the hit to the economy as the "productivity penalty", which amounted to about 1.3% of gross domestic product, GDP is an important tool for looking at how well, or badly, an economy is doing.
£1,000 per household
"That 1.3% of GDP is about £29billion, or roughly £1,000 per household," he added.
Sir Richard Branson is among the business bosses who have suggested the cost of Brexit red tape would put them off investing in the UK.
But the pro-Brexit group Briefings for Business claims there is no evidence of a Brexit-related hit to investment.
A Treasury spokeswoman added that, since leaving the EU single market, the UK had grown faster than France and Germany.
"The government is making the most of our Brexit freedoms to grow the economy, including ambitious financial services sector reforms which will unlock over £100billion of investment, and we are reviewing EU-derived rules in other critical growth sectors this year," she said.
Figures released last week showed that the UK narrowly avoided falling into recession in 2022, but the Bank expects it to enter one this year.