The British government accepts for the first time at the high court that three elderly Kenyans were tortured under the colonial administration half a century ago.

Please wait while this video loads. If it doesn't load after a few seconds you may need to have Adobe Flash installed.

The Kenyans are pursuing claims of torture against the British government, following a British judge's ruling last year which accepted they had a case.

Guy Mansfield QC said: "The government does not dispute that each of the claimants suffered torture and other ill-treatment at the hands of the colonial administration. I do not dispute that terrible things happened."

The Kenyans' lawyer said it was the first official acknowledgement of the crimes in the UK.

However the legal argument expected to be put forward by the Foreign and Commonwealth Office (FCO) will deny ultimate responsibility for the crimes, based on the fact that the legal time limit for accountability has expired, and that the government believes legal responsibility for what happened in detention camps was transferred to the Kenyan republic when it became independent in 1963.

Lawyers for the Kenyans say that Paulo Nzili, Jane Mara and Wambuga Nyingi were subjected to severe brutality in British camps during the 1950s Mau Mau rebellion against British colonial rule. A fourth claimant, Ndiku Mutwiwa Mutua, died during the wait to take the case to the high court. The three Kenyans, who are in their 70s and 80s, have flown 4,000 miles from their rural homes for the trial, which is expected to last two weeks.

But Richard Hermer QC, the lawyer acting for the Kenyans, told the court on Monday that a fair trial was still possible because of the existence of evidence in thousands of official records. The discovery last year of the FCO's secret archive of thousands of files from the colonial era, and the absence of many that were destroyed, was mentioned by lawyers as further evidence of alleged crimes and reason for the Kenyans' case to be heard.

Historians estimate that around 150,000 suspected members of the Mau Mau, a nationalist resistance movement against British colonial rule in Kenya, were detained without trial between 1952 and 1961 and placed in British-administered camps.

Kenyans calling for apology

Supporters of the Kenyans' case include Archbishop Desmond Tutu who said the government should show "magnanimity and compassion" in a letter sent to David Cameron in February, adding that the government was reliant on a "technical legal defence".

Standing outside court on Monday with Mr Nzili, the trio's solicitor Martyn Day said they were pursuing an apology for the abuse they suffered "to be able to live out the final years of their lives with a degree of dignity".

He added: "From the start, they have offered to resolve their case if the government is willing to address their concerns, but to date, the door has been firmly shut in their faces. If the government continues to refuse to open its door to such discussions, they have instructed us to fight on come what may," he added.

Implications for future legal cases

The case raises issues of accountability for the crimes of the British empire, even years after atrocities have occurred. If the British government is forced to take responsibility for the alleged crimes, similar accusations of mistreatment could be brought.

Earlier this year, a group of Malaysians asked the high court to rule that the British government's refusal to set up an inquiry into an alleged massacre on a rubber plantation in 1948 was unlawful. British troops were at the time attempting to counteract the country's communist insurgency.

David Cameron last year apologised on behalf of the British government for Bloody Sunday, when 13 people were killed by British soldiers in January 1972 in Derry, Northern Ireland.

Professor Caroline Elkins, a leading authority on the Mau Mau uprising, said men were castrated and women raped, and that the government in London aware of these atrocities, in her Pulitzer Prize winning book Britain's Gulag: The Brutal End of Empire in Kenya. She has submitted a statement to the court.

Who were the Mau Mau?

The Mau Mau were a nationalist movement who advocated violent resistance to British colonial rule in Kenya, their aim to drive the imperialists out of the country. They were banned by the British authorities in the 1950s, while the Kenyan government declared a state of emergency in 1952 after a Mau Mau campaign of assassination and sabotage. British troops were sent to Kenya, with fighting lasting until 1960, when this state of emergency came to an end.

Although the Mau May were defeated, within three years Kenya had achieved independence from Britain, with the nationalist Jomo Kenyatta elected prime minister in Kenya's first multi-racial elections following years of house arrest.

What happened during the uprising arouses fierce debate, the British administration accused of waging a violent counter-insurgency campaign, relying on beatings and killings to subjugate Mau Mau fighters.

Governor-general Sir Evelyn Baring imposed the death penalty on anyone administering the Mau Mau oath, which often involved forcing tribesmen at knifepoint to kill European farmers when ordered to do so. Sir Evelyn later offered an amnesty to Mau Mau fighters, but the killings continued and the amnesty was withdrawn in 1955.

Estimates vary about how many Kenyans were killed. The Kenya Human Rights Commission argues that 90,000 were executed or tortured and 160,000 people detained during the lengthy suppression of the uprising. Others say between 11,000 and 25,000 died.

Camps were also used, with inmates suffering deprivation and mistreatment. But Mau Mau fighters meted out their own punishment to pro-British Kenyans, raiding loyalist villages and killing those living there. Although British tactics have been widely criticised, and were condemned by some MPs at the time, the Mau Mau were also capable of great cruelty.