A compensation claim against the British government brought by veterans of Kenya's independence struggle has been lodged at the High Court in London.
Three men and two women have launched a case claiming human rights abuses in the 1950s and 1960s.
Thousands of people were rounded up and forced into camps by the British during what was known as the Mau Mau uprising.
Britain says the claim is not valid because of the amount of time since the abuses were alleged to have happened.
The five Kenyans - now aged in their 70s and 80s - are the lead claimants in the reparations case.
They want the government to acknowledge responsibility for atrocities committed by local guards in camps administered by the British in the pre-independence era.
Their lawyer, Martyn Day, said he believed his clients had "a good chance of success".
The government has indicated that the claim is invalid because of the time that has passed and that any liability rested with the Kenyan authorities after independence in 1963.
Mau Mau movement
Historians say the Mau Mau movement helped Kenya achieve independence.
But their actions were also been blamed for crimes against white farmers and bloody clashes with British forces throughout the 1950s.
The BBC reports the armed movement began in central Kenya with the aim of getting back land seized by British colonial authorities.
Veterans of the war say they suffered barbaric treatment, including torture, as the British suppressed the rebellion.
The Kenya Human Rights Commission has said 90,000 Kenyans were executed, tortured or maimed during the crackdown, and 160,000 were detained in appalling conditions.