If Churchill's crimes against humanity in the Middle East don't match Cheney's, then only for lacking the same level of technology.
There is no reason to make a hero out of Churchill. Even at the height of his fame, the moment of victory in WW2, the British themselves understood that he was a dangerous and unscrupulous adventurist who had to go -- great for a twilight struggle against the Nazi beast, a disaster otherwise. So they voted him out of office, right in the middle of the July 1945 Potsdam Conference! Back in a day I talked with UK veterans who fondly recalled voting him out as soldiers!
His crimes are hardly hidden to history: Britain lied to the Arabs during WWI that they would have an independent Arabia, occupied them, drew their borders for them, faced an uprising in Iraq, bombed civilians there, killed many thousands without any regard for human life.
Here's one treatment I found:
http://www.worldfuturefund.org/wffmaster/Reading/war.crimes/World.war.2/Air.Control.htm
At the time Winston Churchill was Secretary for Air and War in the Lloyd George government. Churchill sought ways to police the empire "on the cheap" by using air power to fight insurgents in place of sufficient ground troops (a fateful decision strikingly reminiscent of the strategy employed by American planners in Iraq eighty years later). Iraq, Churchill stated, provided the opportunity to "carry out a far-sighted policy of Imperial aerial development in the future."(3) He therefore asked Trenchard if he thought the RAF could help matters in Mesopotamia. The British had 14,000 regular army troops and upwards of 80,000 Indian soldiers stationed in Iraq at a cost of between £14 million and £18 million per year. This cost had to be cut and Churchill wanted to use air power for financial savings, particularly after the defeat of Ibn Hassan in Somalia. Trenchard said he was confident his planes could help police the territory and suppress the rebellious tribesmen, although it would take some time to get his squadrons up and running in distant Mesopotamia.
Poison Gas against Civilians: Churchill Says Yes
Churchill was at this point willing to use any means necessary to achieve his goals in Iraq, including poison gas bombing, which he actually argued was more "humane" than bombing with explosives. Writing to Trenchard on August 29, 1920, Churchill advised "I think you should certainly proceed with the experimental work on gas bombs, especially mustard gas, which would inflict punishment on recalcitrant natives without inflicting grave injury on them."(4) In his enthusiasm for utilizing the new technology of gas bombing, Churchill was unwilling to admit that even gas irritants could prove deadly to children, the elderly, and the infirm: "I am ready to authorise the construction of such bombs at once; the question of their use to be decided when the occasion arises."(5) Experience proved that many gas "irritants" caused blindness and other physical problems which could not be cured due to a lack of antidotes among the native population, but this was irrelevant to Churchill.
Once deployed in Iraq the RAF proceeded to bomb civilians and tribal insurgents alike. A Kurdish survivor of these attacks later recalled, "They were bombing here in the Kaniya Khoran ... Sometimes they raided three times a day."(6) Wing Commander Lewis, of the 30th RAF Squadron remembered: "one would get a signal that a certain Kurdish village had to be bombed."
Arthur Harris, the man who would later oversee the destruction of German cities during WW II, also saw action in Iraq and participated in the bombing of civilians as a wing commander. He wrote of this experience, "The Arab and Kurd now know what real bombing means in casualties and damage. Within forty-five minutes a full-size village can be practically wiped out and a third of its inhabitants killed or injured."(7) Similarly, J.A. Chamier, another British wing commander, wrote, "The attack with bombs and machine guns must be relentless and unremitting and carried on continuously by day and night, on houses, inhabitants, crops and cattle."(8) By March 1922 the Air Ministry had proven its tactics so effective that it was given control over security in Mesopotamia. For the next decade RAF planes would bomb numerous tribes that continued to defy British rule.
Britain Reserves the Right to Bomb Civilians in Colonial Areas
Events in Somalia and Iraq were indicative of the generally favorable attitude of British officers and politicians toward using aerial bombardment against troublesome subject people. Throughout the interwar period, in fact, Great Britain rebuffed any attempt to restrict its use of bombers against civilians in territories under its control. For example, during disarmament talks in March 1933, Great Britain had submitted the so-called MacDonald Plan, Article 34 of which agreed in principle to a limitation on aerial bombardment "with the exception of police actions in certain distant locations." Two years later, in May 1935, Lord Londonderry then defended Britain's refusal to agree to a prohibition on using aerial bombardment against civilians that had been proposed at the Geneva Disarmament Conference: