Kenya has demanded an apology from the UK for alleged atrocities committed against Mau Mau fighters seeking independence in the 1950s.
British soldiers are accused of rape, torture and killing
Justice Minister Kiraitu Murungi said it was the honourable thing to do to formally apologise for "barbaric crimes against humanity".
War veterans are preparing to sue Britain for compensation, claiming they were tortured in detention.
Official estimates say 11,000 Mau Mau were killed by British forces.
The minister made the comments at the launch of the book Caroline Elkins' Britain's Gulag: The Brutal End of Empire, which details the crackdown of the rebellion and the Kikuyu community.
Ms Elkins, who is a professor at Harvard University, disputes the official death toll saying many more died in the conflict.
"I now believe there was in late colonial Kenya a murderous campaign to eliminate Kikuyu people that left tens of thousands, perhaps hundreds of thousands dead," she writes in the book.
"I call upon the government of the United Kingdom, as a civilised nation to do the honourable thing and issue a formal apology to the Mau Mau, their families and the people of Kenya for these barbaric crimes against humanity," Mr Murungi said.
British servicemen who suffered atrocities at the hands of the Japanese during the Second World War were compensated, he said.
"We do not believe it would be too much to ask the UK government to extend the same principle to the Mau Mau war veterans and their families."
A spokesman from the British Foreign and Commonwealth Office said the UK government understood the issue still created strong feelings in Kenya and that the hardships during the emergency had caused pain on both sides and marred the progress towards independence.
"But this took place 50 years ago. Kenya needs to look to future challenges like fighting corruption, fighting injustice and building a strong democracy," he told the BBC News website.
Relations between the UK and Kenya have recently been strained after the UK High Commission to Nairobi accused the Kenyan government of massive corruption.
Vice President Moody Awori, also at the function, said the British campaign was "cruel and pitiless".
"The fact that colonialists put so much effort to conceal their actions means they knew what they were doing was wrong," he said.
The allegations in the book include rape, torture, murder and theft of property.
"We want the British government to acknowledge their wrongdoing and say sorry," Paul Muite, one of a group of lawyers preparing to sue Britain for compensation on behalf of former Mau Mau fighters, told AFP news agency.
"It's only that way that we can say that our humanity is recognised."