Bercow said he made up his mind about Trump before he ignited a fresh round of outrage by signing an executive order that banned citizens from seven mostly-Muslim from entering the U.S.
"Before the imposition of the migrant ban, I would myself have been strongly opposed to an address by President Trump in Westminster Hall," he said. "After the imposition of the migrant ban I am even more strongly opposed to an address by President Trump in Westminster Hall."
There was no immediate response from the White House to Bercow's snub or from British Prime Minister Theresa May, who had been taking flak from lawmakers from extending Trump an invitation to visit Britain. So far no date for a state visit has been set.
But Bercow is one of three lawmakers who would have to sign off on any Trump address should an invitation be extended, the other two being the Speaker of the House of Lords (the upper house of Parliament) and Lord Great Chamberlain (who runs the parts of the Westminster Palace not controlled by the two houses of parliament).
Bercow stressed that Britain values its "relationship with the United States," but addressing the Lords and Commons are an "earned honor" not an "automatic right."
Three U.S. Presidents have addressed Parliament — Barack Obama in 2011, Bill Clinton in 1995, and Ronald Reagan in 1982. So have leaders of countries that Trump has targeted like Mexico and China as well as religious leaders like Pope Benedict and the Dalai Lama.