A furious George Galloway last night vowed to fight a ban on him entering Canada on the grounds of national security.
The MP for Bethnal Green and Bow had been due to speak at a number of events in the country but his anti-war stance was drawn to the attention of the government by a Jewish group.
He will challenge the decision in court.
A Canadian government spokesman said that the decision would not be overturned for a man regarded as an "infandous street-corner Cromwell".
The description of the Respect MP may have led him to his dictionary the definition of infandous is "too odious to be expressed or mentioned".
Galloway said the comparison to Cromwell was not so offensive as he was "the champion of parliamentary supremacy and the executor of supporters of autocratic and arbitrary power".
Galloway has been deemed "inadmissible" to Canada under section 34(1) of the country's immigration act.
Alykhan Velshi, a spokesman for the immigration minister, said the act was designed to protect Canadians from people who fund, support or engage in terrorism.
"We're going to uphold the law, [and] not give special treatment to this infandous street-corner Cromwell who actually brags about giving 'financial support' to Hamas, a terrorist organisation banned in Canada," said Velshi.