Brexit has cost the British economy £550 million a week since the referendum, a report has found.
Standard & Poor's suggested that since the June 2016 vote, 3 per cent has been shaved off GDP.
That equates to "forgone economic activity" of £6.6 billion in each of the 10 quarters since the referendum, or £66 billion, the credit ratings agency said.
The group said the UK's economic performance has suffered from the "mere anticipation" of Brexit.
"The most visible effect has been the depreciation of the British pound, which triggered an increase in inflation. The ultimate result was to erode household spending power,” the report said.
"Household spending would have been considerably stronger - in line with GDP - had the referendum not occurred," S&P said in its publication, Countdown To Brexit: What Might Have Been For The UK Economy.