The same declassified papers show that Churchill also wanted Adolf Hitler executed "like a gangster" in an electric chair borrowed from the Americans, if the dictator were captured alive by British troops.

The plan to attack small villages "on a three-for-one basis" was formed in the summer of 1942 five days after German forces murdered most of the 450 occupants of Lidice, a village north of Prague, in retaliation for the assassination of Reinhard Heydrich, deputy leader of the SS.

Churchill abandoned the plan only in the face of opposition from cabinet colleagues, who feared that the lives of aircrews would be placed needlessly at risk. Clement Attlee, the dominions secretary and future Labour prime minister, said he believed it unwise "to enter into competition in frightfulness with the Germans". On June 15 Churchill conceded, saying: "My instinct is strongly the other way ... I submit unwillingly to the view of cabinet against."

The existence of the village raids plan is disclosed in notebooks kept by Sir Norman Brook, the wartime deputy cabinet secretary, who recorded cabinet meetings. His notes, now made public by the National Archives at Kew, south-west London, also show that Churchill was determined to execute Hitler. "Contemplate that if Hitler falls into our hands we shall certainly put him to death," Sir Norman recorded the prime minister as saying in December 1942, on one of the few occasions that the cabinet discussed what to do with the Führer. "Not a sovereign who could be said to be in hands of ministers, like Kaiser. This man is the mainspring of evil. Instrument - electric chair, for gangsters, no doubt available on lease-lend." He was referring to the arrangement with the US which helped to fund the British war effort.

In April 1945, the home secretary, Herbert Morrison, expressed the opinion, seemingly popular with his colleagues, that a "mock trial" for Nazi leaders would be "objectionable", and said that it would be "better to declare that we shall put them to death". Churchill agreed that a trial for Hitler would be "a farce", adding that "all sorts of complications ensue as soon as you admit a fair trial".

Churchill supported a proposal to circumvent the allies' commitment to such trials by writing to the Soviets and Americans explaining Britain's justification for summary justice, and then carrying out the executions before either had time to reply. A list of Nazis who were to be shot without trial was to have been prepared.

As the war came to an end, and with many of Germany's wartime leaders taking their own lives, Churchill apparently decided that it was not worth "a big fight" with the other allied nations. Even then, however, he was asking cabinet colleagues whether they could, in theory, negotiate with Himmler, "and bump him off later?"

Churchill's ruthlessness emerges elsewhere in Sir Norman's notes, where he is quoted as saying that German PoWs in British hands should be shot if the Nazis began killing British captives.

'Gandhi can die'

Winston Churchill was prepared to let Mahatma Gandhi die if he went on hunger strike while interned during the second world war, according to declassified war cabinet documents.

The wartime prime minister felt that the Indian leader should be treated like any other prisoner if he stopped eating after he had been detained in 1942 for condemning Indian involvement in the war against Hitler and for calling for civil disobedience.

Some leading figures feared an uprising if Gandhi died. But Churchill was incensed by the prospect of granting him a moral victory: "I would keep him there and let him do as he likes," the papers quote him as saying. "But if you are going to let him out because he strikes, then let him out now."

Eventually, ministers decided in January 1943 that although they could not publicly give in to a hunger strike, they would be willing to release Gandhi on compassionate grounds if he seemed likely to die. He was freed the following year.

Other papers show that British troops were told to show respect for the US army's racial segregation policies by showing "reserve" when meeting black troops stationed in Britain during the war. The guidance was issued after anguished debate in Churchill's cabinet over how to deal with discriminatory American rules.

Hundreds of thousands of black troops, mostly from colonies, were expected to be treated equally in the British Empire's armed forces, while white US soldiers ate and slept separately from their black comrades.