“Partly for economic reasons – being part of a big trade bloc – and partly because I think we’re in a world of power blocs.”
He added: “For all the weaknesses and deficiencies of the European Union it’s better to be in that big power bloc in the world than thinking you can act as effectively on your own under a lot of supranational and multilateral and global challenges.
“I think we’re better placed to try to address as part of a group… so I voted to remain.
Mr Bercow has the deciding say on who gets to speak in the Commons and will oversee debate on various elements of Brexit unless deposed by Parliament.
His comments, made just three days before his public display of disapproval for President Trump, could be in breach of Parliamentary rules that stop the Speaker from being drawn into taking sides in political debates.
Parliamentary rules state: “The Speaker is the chief officer and highest authority of the House of Commons and must remain politically impartial at all times… therefore, on election the new Speaker must resign from their political party and remain separate from political issues even in retirement.”
His comments have led Conservative MPs, who had already tabled a no confidence vote over the Speaker’s handling of President Trump’s state visit, to claim he is “incapable” of guiding the house through Brexit.
James Duddridge, Conservative MP for Rochford and Southend East, said: “Speaker Bercow cannot come back to the chair having expressed views on Brexit.
“He is incapable of chairing Parliament as Speaker on any European business.”
Tory MP Alec Shelbrooke added: “John Bercow’s comments are in clear breach of the guidelines laid down on the independence of the Speaker of the House.”
A spokesperson for Mr Bercow said: “The Speaker’s impartiality is required on matters of debate before the House, and he has been scrupulous in ensuring that both sides of the argument are always heard.
“Furthermore, his comments made clear that he absolutely respected the result of the referendum.”
“How he voted and whether or not he said how he voted after the event is completely irrelevant.
“It had absolutely no bearing on his impartiality.”