A speech-writer for the Canadian Conservative Party has resigned after Prime Minister Stephen Harper was accused of plagiarising a speech he made in 2003.
Owen Lippert admitted he had been "overzealous in copying segments" of a speech in support of the invasion of Iraq by then Australian PM John Howard.
Mr Lippert said neither his superiors nor Mr Harper, who was opposition leader at the time, had been aware.
The accusation comes half-way through a general election campaign.
Mr Harper called the snap election for 14 October last month, hoping to either bolster his minority, or obtain a majority government, for which he would need to win 28 more seats in parliament. Opinion polls suggest he is within striking distance of doing so.
The speech by Mr Harper was originally made on 20 March 2003 as the House of Commons in Ottawa held an emergency debate at the beginning of the United States-led war in Iraq.
In the debate, Mr Harper urged Canada and the Liberal government to join the so-called "coalition of the willing".
Five years later at a campaign stop on Tuesday, during an increasingly bitter election campaign, Liberal MP Bob Rae made an incendiary accusation.
Mr Harper's 2003 speech had been made almost word-for-word two days before in Canberra by John Howard, he said.
And just to prove it, portions of the speech were played side by side.
"In the interests of world peace and regional security... The community of nations required Iraq to surrender," Mr Howard said in his speech.
"In the interests of peace and regional security... The community of nations required Iraq to surrender," Mr Harper said days later.
Conservative campaign officials initially refused to discuss the matter, but eventually Mr Lippert announced his resignation.
The revelation comes during an election campaign that has focussed heavily on leadership, with Mr Harper depicting himself as honest and dependable, contrasting himself to the main opposition Liberal leader, Stephane Dion.
Mr Dion is behind in the polls and has been criticised for poor leadership and communication skills.