Speaking in his first broadcast interview, Mr Kember said it was "ironic" that such a committed pacifist was freed by elite special forces, as he also revealed that he considered suicide during his 117 days of captivity.
The Christian peace activist also disclosed that he and his two Canadian fellow captives were freed after the British-led force had arrested and interrogated their chief kidnapper, an Iraqi they had nicknamed "medicine man".
Mr Kember, 74, also said he and his wife, Pat, had amassed a stack of hate mail sent to their home in Pinner, north London. One attacked him for being ungrateful to the British soldiers who released him.
But the Briton insisted he continued to thank his rescuers, rejecting claims by Gen Sir Mike Jackson, the head of the armed forces, that he was ungrateful. "They were brave. I disagree with their profession, but it is ironic, isn't it? You go as a peace activist and you are rescued by the SAS, which is perhaps the most violent of all the British forces. Anyway, I am grateful to them."
Mr Kember's interview, broadcast yesterday on Radio 4, gave a revealing insight into his ordeal after he was kidnapped at gunpoint in a Baghdad suburb last November. The Briton, 74, had only recently arrived in the Iraqi capital to take part in a peace mission with the US-based pacifist Christian Peacemakers Team. He and three other CPT members - Tom Fox, an American former Marine, and two Canadians James Loney and Harmeet Singh Sooden - had just visited a senior Shia cleric when they were seized by four gunmen. "It was sort of an odd feeling: is this actually happening to me? It seemed unreal."
At several points - particularly when he described the moment the SAS burst into the house where he was being held - Mr Kember became noticeably distressed. His voice also broke with emotion when he recalled praying to be back at home.
On the morning of their release, on 23 March, the hostages were lying on mattresses. "We weren't expecting anything ... Suddenly we heard a noise outside and then somebody calling out and then breaking of glass and then up the stairs came these SAS gents. The two minders had disappeared - they must have been forewarned by mobile phones to get out. And the only one who came with the SAS group was Medicine Man and he was in his nightgown." Mr Kember suspected that Medicine Man, captured the previous day, had tipped off the minders.
During his captivity Mr Kember considered killing himself, because as a Briton, he was the most politically useful captive left. "I thought it might help the Canadians. If they got rid of the Brit then they might find it easier," he said.
Their four kidnappers included a volatile 25-year-old they called "Junior", whose family had been killed in the bombing of Fallujah. An affable man who aired their room was called "Uncle", and the third was "Nephew". Medicine Man earnt his name because he had bought Mr Kember his blood pressure tablets.