John Longworth, of Leave Means Leave, said Brexiteers would have been celebrating an even bigger win had parliamentary constituencies been taken into account.
The former director-general of the British Chambers of Commerce added the British public was given “misinformation” about what the economy would look like post-Brexit and certain bodies had purposefully not revealed any likely benefits.
Speaking on RT, Mr Longworth said: “The simple fact of the matter is that two thirds of constituencies in the UK and three quarters of parliamentary constituencies in England and Wales voted to leave the European Union.
“Had it been a general election, that would have been a landslide victory for the Leave party.”
John Longworth said if Brexit had been a general election it would have been a "landslide victory"
Had it been a general election, that would have been a landslide victory for the Leave party
Mr Longworth was suspended from his job at the Chamber after saying the UK could have a “bright future” outside the EU.
The campaign group co-chair added the UK economy was “doing very well” and was set to perform at the same level next year as well.
He said the public was fed “misinformation” by experts in the run up to the referendum, about the impact Brexit would have on the UK economy.
“Clearly there was misinformation promulgated during the campaign, most of the information that came out of the institutions, not only in the UK but in the European Union, and of course also Government bodies such as the treasury department were designed to exclude positive elements of Brexit," he said.
In pictures: Theresa May meets with EU's Tusk Thu, April 6, 2017
The two leaders held talks on Brexit negotiations
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European Council President Donald Tusk gestures to members of the media as he leaves 10 Downing street after talks with British Prime Minister Theresa May in central London
“So they were actually skewed towards misinformation to suggest that the UK would do very badly and they’ve all me proved to be incorrect.
“There were of course economists saying the reverse but they weren’t widely reported. The fact of the matter is that the UK economy’s doing very well.
“Highly likely to do very well next year as well.”
Britain could be given temporary admission to a trade group so it can continue to do business with the European Union after Brexit, according to a plan being drawn up in Brussels.
EU insiders told Politico that Theresa May’s nation may be accepted into the European Free Trade Association until a permanent model is established – which would benefit Brussels members, but not necessarily Britain.