The call is seen as an attempt to put pressure on Gordon Brown, the British finance minister who is set to take over from Prime Minister Tony Blair at the end of the month.

William Hague, the Conservative spokesman on foreign affairs, said he would use a debate in the House of Commons to push for a hearing with the power to summon officials and military commanders for questioning.

"It's very important, for instance, to find whether there are lessons that need to be applied to Afghanistan from what has happened in Iraq for the last years," Hague told BBC radio.

Britain has in the last year been increasing its deployment of soldiers to Afghanistan, where they are fighting a resurgent Taliban, while pledging to reduce troops in Iraq.

"It's very important to start an inquiry by the end of 2007 into events that happened back in 2003, unless memories are going to have faded and many emails are going to have disappeared," Hague said.

"And I think a proper inquiry into Iraq is also essential to restoring public trust and confidence in the government or any government when it comes to take decisions about matters of this kind," he added.

Hague said the inquiry should look at the decision to disband the Iraq army and Iraq's ruling Baath party, which Washington and London accept as one of the "calamitous decisions" in the course of the occupation.