Eleven members of parliament (MPs), mainly Scottish and Welsh nationalists who opposed the war, plus two opposition Conservatives, want to use the dated practice to force Blair to defend himself at Westminster over his decision to go to war. 

"Although no one voted in this country for george Bush, we have fought his war and followed his disastrous foreign policy," said Angus Robertson, and MP with the Scottish Nationalist Party (SNP).

"Going to war in Iraq was a done deal made behind the back of parliament and the people."
   
Although it has almost no chance of success, the plan will throw the spotlight back on the reasons Blair gave the country for going to war, British newspapers said on Thursday.
   
The backlash over Iraq has seen Blair's trust rating plummet, and although opinion polls say he is on course to win a third general election expected next year, opponents hope to use the issue to question his credibility. 
 
Rare step

The impeachment process can be invoked against any person accused of "high crimes and misdemeanours" if a single MP persuades parliament there is a case to answer.

"This campaign shows those who supported the war were lied to and they are now seeking to impeach Blair for that"

Scottish National Party spokesman

"This will be the first time a group of MPs has taken this step for over 150 years," Welsh nationalist Adam Price said.

It was last used in 1848 and was last successfully invoked almost 200 years ago in 1806, newspapers said. 

In 1967 a parliamentary committee recommended the right to impeach should be abandoned as "the circumstances in which impeachment has taken place are now so remote from the present that the procedure may be considered obsolete".
   
However, the right was never repealed. 
   
Only option

The 11 MPs said they wanted to use the power because they believed Blair acted dishonestly in taking Britain to war by overstating the threat posed by Iraq.

"It's against the rules of the House of Commons to accuse another MP of being dishonest so impeachment is the only option open," a spokesman for the SNP told Aljazeera.net.

"Ministers must resign if they mislead Parliament," he added. 
   
"This campaign shows those who supported the war were lied to and they are now seeking to impeach Blair for that," the SNP spokesman said, commenting on the involvement of two Conservative MPs in the campaign.

A top-level inquiry in July cleared Blair of tricking Britain into war but did criticise him for relying on deeply flawed pre-war intelligence.