Secret tapes of 'professional sadists' reveal true story of German soldiers' war brutality

The captured Luftwaffe fighter pilots were swapping shocking stories about the raids they had flown over Kent during the opening stages of the Battle of Britain. They had no idea that their room was bugged and their conversation was recorded by Allied intelligence.

"I was over Ashford," said one who recalled flying low over the town in a so-called "disruption attack". "Some sort of meeting was being held on the market square. Masses of people, speeches and all that. They didn't half get spattered! That was fun!" he added.

Not wanting to be outdone, his colleague countered: "We did a low level attack on Eastbourne. We got there and there was this big house with a ball going on. There were lots of women in evening gowns and a band. The first time we just flew past. Then we turned round and gave it to them! My dear fellow, THAT was fun!"

Yet another boasted: "In our squadron, I was known as the 'professional sadist'. I knocked off everything: buses, a civilian train in Folkestone. I gunned down every cyclist."

These macabre exchanges are among some 13,000 bugged conversations between captured German servicemen at the Trent Park detention centre in north London during the Second World War. The Allies recorded them in the hope of obtaining strategic information and excerpts from the 150,000 pages of transcripts will be published for the first time next week in Soldaten – which means "soldiers".

It is a disturbing book by two German historians which reveals the barbaric attitudes of some of the ordinary men who fought for Germany in the war and dispels the myth that chivalry played a role in the Luftwaffe during the Battle of Britain. It also suggests that millions of servicemen became brutalised almost as soon as hostilities began.

As one pilot said of the invasion of Poland in 1939: "I had to bomb a station but eight of the 16 bombs fell on houses. I didn't enjoy that. By the third day, I didn't care and on the fourth day, I enjoyed it. It was a pre-breakfast pleasure to chase soldiers through the fields with machine-gun fire."

The authors, Sönke Neitzel and Harald Welzer, discovered the recordings while searching in British and US military archives for material about the German U-boat war. They expose a German U-Boat rating's glee at having "knocked off a child transport" carrying more than 50 refugee children which his submarine had just sunk in the Atlantic.

In another case, a senior German army officer voiced his disgust at a junior lieutenant's giggling account of how he and his men raped a so-called woman "spy" in Russia and then threw hand grenades at her. "She didn't half scream when they exploded near her," the lieutenant jeered. The recordings also show, not for the first time, how the regular German army, or Wehrmacht, often delighted in taking part in the Holocaust: "The SS sent out an invitation for a Jew shoot," recalled one lieutenant colonel on the Russian front. "The whole company went along with rifles and gunned them down. Each could choose who he wanted to knock off." The book is certain to cause a stir in Germany. It may also reopen a major controversy that erupted in 1995 when historians staged a travelling exhibition about the regular army's role in the Holocaust.

Crimes of the Wehrmacht sparked protests and led several critics to dismiss it as a falsification. It was never turned into a permanent exhibit.