Tony Blair may have put his finger on the obstacle to freeing Ken Bigley from his captors in Iraq when he said: "There is no need in raising false hopes, because of the nature of the people we're dealing with." The people he is dealing with, of course, are in Washington. It would be difficult to design policies more certain to prevent Mr Bigley's safe return that those which the Bush administration is pursuing in Iraq.

First, they assassinated the spiritual leader of Abu Musab al-Zarqawi's Jamaat Tawhid wal Jihad (Unity and Holy Struggle Group). This is the organisation responsible for abducting Mr Bigley and two American colleagues, Jack Hensley and Eugene Armstrong.

Second, they prevented the interim Iraqi administration - itself a creature of Washington - from allowing its courts to release two female detainees when the kidnappers were demanding that all women in Iraqi and US prisons be freed. (Iraqi officials had said they had no evidence to justify holding the women, until American officials weighed in to persuade the new Iraqi administration not to be seen to be yielding to terrorism. The interim government, despite its nominal independence, yielded to the US.)

Third, US forces have repeatedly bombed Fallujah, where they say the kidnappers' organisation is based. Would such bombings - which Agence France Press reported had killed 15 Iraqi civilians on Sunday and 11 the day before - provoke extreme reaction or make it easier for the kidnappers to respond to humanitarian appeals from Mr Bigley's family, the Muslim Council of Britain, the singer Yusuf Islam (Cat Stevens) and many others since his kidnapping on 16 September?

Iyad Allawi, the former Baathist, former CIA asset and current interim Prime Minister of Iraq, voiced a policy that will please his masters in Washington: "We have not been negotiating, and we will not negotiate, with terrorists on the release of hostages." Why not?

Everyone who wants hostages to return home alive negotiates with kidnappers. It happened over the American embassy hostages in Iran in 1979. It happened in Beirut during the 1980s, when many Britons and Americans - including myself - became captives of the Shia Muslim Hizbollah (Party of God). It happens almost every day in the United States, where police and other mediators negotiate as long as possible with criminal or psychotic kidnappers to keep hostages alive. Negotiate is what you do when you want to save hostages' lives. If not, you leave them to rot.

As the US Secretary of State, Colin Powell, admits, violence in Iraq is escalating. More and more Iraqis and some Arabs from other countries are intensifying the battle against American-British occupation. The conflict has killed a thousand American soldiers and
many more Iraqis. A recent report by the Iraqi Ministry of Health concluded that, between April and September this year, American troops had killed twice as many Iraqi civilians as the insurgents had. The insurgents have targeted those - the new police, army and civil administration - whom they see as collaborating with the American project. But the Americans have caused two-thirds of the 3,487 Iraqi civilian deaths recorded by the ministry. The US Knight-Ridder news agency, which published details of the report on Saturday, quoted a ministry official: "Anyone who hates America has come here to fight: Saddam's supporters, people who don't have jobs, other Arab fighters. All these people are on our streets. But everyone is afraid of the Americans, not the fighters. And they should be."

The treatment of Iraqi prisoners in American custody - typified by the Abu Ghraib scandal that the Bush administration has relegated to political insignificance in the US - has exacerbated tensions in Iraq. It has also made taking civilians from the other, Western side more acceptable to Iraqis.

Sheikh Abdel Sattar Abdel Jabbar, an Iraqi Sunni religious scholar and opponent of American occupation, condemned the kidnapping of two French journalists and two female Italian aid-workers in Iraq. "They are innocent," he said on al-Jazeera television. However, the sheikh distinguished them from Mr Bigley and the two Americans whom the kidnappers beheaded. The three Westerners worked for Gulf Services Company of the United Arab Emirates on a contract to build and support an American military base north of Baghdad. Sheikh Abdel Sattar said that they were men "who build bases to wage war on the Iraqi people". However, in war, no one is allowed to murder unarmed prisoners. This is as true for Muslims as for Christians and atheists.

The long-term solution to the kidnapping of Westerners in Iraq is what it was in Lebanon: the foreign armies should leave. Hizbollah stopped kidnapping foreigners in 1991, when it released Terry Waite and Terry Anderson. Their freedom took place against a background of Israel's withdrawal from most of Lebanon and the successful negotiations by the United Nations mediator, Giandomenico Pico, with Hizbollah's benefactors in Iran.

In the short term, Britain could hold secret contacts with the militants or their go-betweens. The US could help all hostages and future hostages by committing itself to observe and enforce the Geneva Conventions on Prisoners of War and call upon the insurgents to do the same. This would allow international oversight of prisoners on both sides. But that would mean recognising the insurgents as co-belligerents in a war that the US prefers to say is against no people at all - only against an apparition called terror.