The existence of German-speaking units fighting for the Allied cause during WW2 has remained largely a well-kept secret. But seventy-five years on these units’ contribution to victory needs to be fully acknowledged.

Prime Minister Winston Churchill had no qualms about using native German speakers from Austria, Poland, Czechoslovakia and of course Germany itself. The majority were Jews who had fled persecution.

Two examples of these secret units were X Troop Commandos and the Special Interrogation Group.

The SIG men deserve their legendary status. They fought, and often died, wearing Wehmacht uniform. As this superbly researched book reveals that, after infiltrating Field Marshal Rommel’s Afrika Korps, one detachment even drew Nazi pay. Inevitably once the existence of SIG units became known, their immediate execution on capture was ordered, unless their temporary reprieve would reveal intelligence under torture.

We learn how Churchill’s initiative was copied by both the Americans and the Russians.

Post-war SIG and X Troop survivors joined British special forces or were used to hunt down Nazi war criminals.

All this and more is covered in this ground-breaking book by a writer who is both a leading historian and foreign correspondent.