And this is how the British got results in WW2
Thousands of German POWs held captive in England during World War II were bugged by "secret listeners" who were themselves German, working for the British. Historian Helen Fry and one of the last surviving listeners explain how the prisoners were lulled into divulging secrets of the Nazi war machine.
One group of German generals captured during World War II thought they had hit the jackpot.
Held in a stately home, they were allowed to keep personal servants, drink wine and eat good food.
As a result they boasted of how stupid the British were, and one even wrote to his family to wish that they could join him at his prison, as he rated it so highly.
But what the prisoners did not know was that British intelligence had bugged every part of their accommodation, from lampshades and plant pots right down to the billiards table around which they relaxed on lazy days.
They were gleaning information about the psyche of the Nazi military from the idle gossip flowing between the prisoners.
Carefully listening in on their conversations were fellow Germans of Jewish origin who had fled from the Nazis.
The bugged prisoners were kept in three locations - Latimer House near Amersham, Wilton Park near Beaconsfield, both in Buckinghamshire, and Trent Park near Cockfosters in north London. The first two held captured U-Boat submarine crews and Luftwaffe pilots, who were bugged for a week or two before being moved on to conventional captivity.
The generals, whose numbers eventually reached a peak of 59 as the war progressed, resided in Trent Park until the war ended.
Hidden nearby in each of the three stately-homes-turned-prisons were the pro-British Germans, listening in a place known as the "M room" - the "m" stood for microphoned - where "secret listeners" were glued to the bugging devices.
Historian Helen Fry, who has written a book called The M Room: Secret Listeners who bugged the Nazis., says the information gleaned by the eavesdropping of the German generals was vitally important to the war effort - so much so that it was given an unlimited budget by the government.
She believes what was learned by the M room operations was as significant as the code-breaking work being done at Bletchley Park.
"British intelligence got the most amazing stuff in bugging the conversations. Churchill said of Trent Park that it afforded a unique insight into the psyche of the enemy. It enabled us to understand the mind-set of the enemy as well as learn military secrets.
"If it wasn't for this bugging operation, we may well have not won the war."
Mrs Fry said the conversation transcripts, which numbered more than 100,000, provided the British with "most of what we knew" about Germany's military capability, its weaponry and its new development of technology during the war.
Through intelligence pieced together from prisoner conversations, the British were able to identify and heavily bomb a V2 rocket site in May 1943 at Peenemunde on the northern coast of Germany, which was preparing to launch deadly rockets at Britain.
Crucially, she adds, the bugging was the first time the British overheard admissions that the German army had taken part in the atrocities and mass killing of Jews and were guilty of war crimes.
"The army had always denied it and that was believed for the last 65 years. What the transcripts show us now is that the German army - with the SS - was complicit in war crimes," she says.
See, no need to commit war crimes to get results, I bet it was far more productive milking senior officers compared with torturing thousands of random Iraqis who had nothing to do with AQ or the insurgency.