Prime Minister Stephen Harper made his pitch for a trade deal between Canada and the European Union in a speech to the British parliament Thursday, saying it would benefit both sides.

"For Canada, and for Great Britain as a member of the EU, this will be a historic step – a monumental one," Mr. Harper said in his prepared remarks. "A joint Canada-EU study has shown that a commercial agreement of this type would increase two-way trade by 20 per cent."

He also thanked British Prime Minister David Cameron for backing the deal. "I should like to express my deep appreciation to you and to your government, for your robust advocacy on behalf of this agreement."

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Mr. Harper spoke to about 100 Members of Parliament and Lords in the "robing room", the traditional place in the British House of Commons for such speeches. The ornate room is where the Queen typically dresses in robes and waits before giving her address to open parliament.

Outside Westminster a small group of striking foreign service workers picketed, holding signs and a Canadian flag. About a dozen staff from the Canadian High Commission in London are on strike along with dozens at other embassies.

Mr. Harper and Mr. Cameron, both Conservatives, clearly enjoy a close relationship. This is their second meeting in three months and they are on a first-name basis.

In his speech, Mr. Harper offered words of support for Mr. Cameron's economic policies which have come under attack in Britain for focusing too much on spending cuts "I acknowledge and applaud your own leadership in taking tough decisions to rein in spending," he said. "And I know you are making the tough decisions, because you believe, because you understand …they are the right decisions, the necessary decisions."

He also invoked former Prime Minister Margaret Thatcher, who died in April and whose legacy Mr. Cameron has tried to adopt, saying she showed great resolve during tough economic times.

"Perhaps more relevant today is the example of Mrs. Thatcher, who, in a time of peace, refused to accept any suggestion of an inevitable decline," he said.

"She did so, not as an expression of good cheer, but as a matter of resolve and action …and so Britain rose once more."

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Mr. Harper spoke at length about global trouble spots, pointing out how Canada and Britain shared similar outlooks. He noted Canada's support for Britain's claim to the Falkland Islands and lashed out at his usual foes, North Korea and Iran.

"This is a profoundly malevolent regime," he said of Iran. "That threatens us all, and whose first victims are the Iranian people."