Anti-war protesters in Britain are preparing to leave for Iraq to volunteer to be so-called "human shields" at key Iraqi installations in case of a U.S.-led war.

The first 50 volunteers plan to leave on Saturday from London City Hall aboard two double-decker buses for what they plan to be a two-week drive to Baghdad.

Along the way, they intend to pick up more voluntary human shields, who plan to camp out at hospitals, water treatment plants and similar facilities in the event a war breaks out over Iraq's suspected arsenal of weapons of mass destruction.

Ahead of their departure, several of the volunteers went to the residence of Prime Minister Tony Blair to drop off photocopies of their passports and a list of places in Iraq where they plan to deploy.

The leader of the group, Ken O'Keefe, explained why the material was delivered.

"Tony Blair has been notified that British citizens, U.S. citizens and others in our democracies are going to be in harm's way and we will be killed by our own governments should they carry out this war as they intend to do right now," he said.

Mr. O'Keefe is a former U.S. Marine and veteran of the 1991 Gulf war that ended Iraq's occupation of Kuwait. He describes his participation in the human shield effort as "penance" for his service in that war.

There has been no comment from Mr. Blair's office about the volunteers' visit to Number 10 Downing Street. British government officials say there are still no plans for a war in Iraq, although the pace of the U.S. and British military buildup in the Persian Gulf region is quickening.

The leader of the self-styled Muslim Parliament of Britain, Ghayasuddin Siddiqui, told a news conference he endorses the human shield project. Mr. Siddiqui's group is a non-governmental organization founded to promote the social welfare of Britain's Muslims. He asserts that Mr. Blair is out of touch with British public opinion on Iraq.

"This country is solidly behind the anti-war movement," he said. "Blair has tried to persuade the people by releasing the Iraq weapons dossier but it didn't work. Then he released the Iraq human rights dossier. Even that one didn't work."

Polls released this week show an upswing in anti-war sentiment among the British public, but by a two-to-one margin they would support a war with Iraq if the U.N. Security Council votes for it.