Thousands of jobs were put at risk after banking giant HSBC threatened to move its headquarters from London to Hong Kong in light of the result of the June 23 referendum.
While Allianz Global Investors’ parent group warned of the risk of “political fallout” following the UK’s exit from the EU.
The Treasury, Bank of England and the International Monetary Fund (IMF) were also among the economic elite that participated in financial scare-mongering over a Leave vote, including a stock market and house price crash.
But the chief economist of the Bank of England has now conceded warnings of an economic crash were premature, describing it as a “Michael Fish moment”.
And now three of the City of London’s most powerful figures are being forced to face a panel of steely-faced MPs to defend their actions.
Chairman of HSBC Douglas Flint, London Stock Exchange boss Xavier Rolet and Allianz Global Investors vice chairman Elizabeth Corley will appear before the Treasury Select Committee on Tuesday.
MPs are due to assess the likely impact of Brexit on businesses, but the parliamentary body is also looking at whether financial firms have exaggerated the threat to services.
It is believed many firms embellished details about the potential impact on the Square mile in an attempt to pressure the Government into putting the financial services at the forefront of Brexit negotiations.
Andy Haldane, Bank of England economist, admitted some banks had been guilty of scaremongering during the lead up to the UK referendum.
Conceding some bleak Brexit forecasts might be “just scare stories”, he also accepted the economy was not in “crisis”.
Kevin Dowd, member of Economists for Brexit group, said: “The overwhelming majority of economists and supposedly respected bodies have been proven spectacularly wrong on the short-term impacts of Brexit.
"Mostly, these forecasts were based on the poorly-evidenced effects of supposed policy ‘uncertainty’ and expected lower growth potential outside the EU.
"As it turned out, the economy had a strong head of steam going into the vote and a positive recovery in the weeks and months following, with GDP figures in particular demonstrating that uncertainty has not undermined economic performance."
In further evidence that scare-mongering experts were wrong, economic growth jumped to 0.6 per cent in the third quarter of 2016 - the three months immediately following the vote.
The meeting comes after Theresa May indicated the UK will leave the single market following Brexit negotiations.
Speaking over the weekend, she said the UK cannot expect to be able to retains “bits” of its membership after quitting the Brussels bloc.
She also promised to provide “more clarity” over the government’s secretive strategy in the coming weeks, amid claims Mrs May has no plan for Brexit.
The City of London has been told it will not get any special treatment in the upcoming negotiations.
Chancellor Philip Hammond and Brexit Secretary David Davis told a group of top bosses that financial services cannot be seen to be treated differently - despite accounting for 11.8 per cent of gross domestic product (GDP).