The British government immediately said it would appeal the High Court judgement, which came after a two-week hearing in July.
The court heard allegations then that Jane Muthoni Mara, Paulo Muoka Nzili and Wambugu Wa Nyingi were subjected to torture and sexual mutilation.
The trio’s lawyers said Nzili was castrated, Nyingi severely beaten and Mara subjected to appalling sexual abuse in detention camps during the Mau Mau rebellion.
Nyingi was caught up in beatings that led to the deaths of 11 men at the Hola camp in 1959, now known as the “Hola Massacre”.
A fourth claimant, Ndiku Mutwiwa Mutua, has died since legal proceedings began.
High Court judge Richard McCombe ruled on Friday that “a fair trial on this part of the case does remain possible and that the evidence on both sides remains significantly cogent for the court to complete its task satisfactorily”.
The judge said: “I am justified in concluding that the available documentary base is very substantial indeed and capable of giving a very full picture of what was going on in government and military circles in both London and Kenya during the ’emergency’.”
Supporters of the Kenyans wept when they heard the judgement, although the claimants themselves were not in court.
In the Kenyan capital Nairobi, around 150 Mau Mau veterans gathered at the country’s Human Rights Commission, singing and shouting as the news broke.
Some of the now frail and elderly veterans – men and women – performed a shuffling celebration dance.
In London, Martyn Day, the lawyer behind the claims, called it a “massive, massive decision” but urged the government to act quickly as his elderly clients “won’t last for much longer”.
“It’s been a long battle,” he told AFP outside the London court. “Many times I thought we’d never reach this point.”