The Mau Mau rebellion of 1952-60 was one of the most savage wars of independence ever fought in Africa. What began as the campaign for land and freedom of a ragtag band of fighters became a nightmare for the colonial authorities. Until now, the blame for the conflict has fallen squarely on the shoulders of the Kikuyu tribesmen who formed the Mau Mau movement. Quite rightly, they have been condemned as evil and barbarous: their brutal and headline-grabbing tactics included displaying the heads of white settlers on spears outside their homes. In Britain's Gulag, however, Caroline Elkins shifts the burden of blame from the Mau Mau to the colonial government and white settlers.

Relying on numerous witness testimonies, Elkins depicts the 1950s as a decade when Britain, in contravention of the human rights conventions it signed after the Second World War, officially perpetrated or abetted prisoner abuse, rape, torture and murder. The "Gulag" of her title refers to the punitive system of torture, forced labour, detention and murder that the British established in order to crush the Kenyan rebellion.

Britain's Gulag opens with a measured and honest account of the tensions that led to the outbreak of guerrilla war, but much of what follows lacks rigour and objectivity. The author appears so shocked by the savagery of the British forces that she sets aside the atrocities of the Mau Mau, almost to the point of excusing them. (A case in point is the Lari massacre, in which Mau Mau fighters torched a village and killed at least 100 people.) Despite a bibliography running to hundreds of titles, Britain's Gulag is full of soppy stories and questionable assertions - such as Elkins's claim that Africans were "much more accomplished agricultural producers than the settlers".

At one point, she writes: "Only by detaining nearly the entire Kikuyu population of 1.5 million and physically and psychologically atomising its men, women and children could colonial authority be restored." Yet the figure of 1.5 million seems dubious - it is not usually thought that the Kikuyu population at the time exceeded one million. Nor does Elkins produce the evidence to justify her revision of the numbers killed during the conflict from 10,000 to 100,000.

She divides the combatants into two camps: the British settlers and their government, and the Mau Mau freedom fighters. Things were more complicated than that, however. There was a class dimension to the struggle. Many Kikuyus were perfectly happy to fight on the side of the colonial authorities to preserve the status quo. This was never a straightforward battle between white and black.

Today in Kenya, the Mau Mau war is still a subject that stirs emotions, and a political hot potato. Virtually all Kikuyus claim to have belonged to the Mau Mau, regardless of whether they were even alive in the 1950s. Africans love stories: they tell them and retell them over and over again. Tales are communally owned, and it is not considered an abominable act of plagiarism to present another person's story as your own. All this makes Elkins's reliance on oral testimonies problematic.

David Anderson's Histories of the Hanged, covering the same period, is a more considered and dispassionate account of the atrocities committed by the British in the 1950s. Anderson relies on court and other records to expose the shame of an imperial system of justice that led to more than a thousand Africans being hanged. Throughout Histories of the Hanged, Anderson condemns the dirty tricks of the British and the Mau Mau with equal vigour. As a result, his book is a more believable account of this sorry episode than Britain's Gulag.

Kwamchetsi Makokha is associate editor of Kenya's Sunday Standard