Three survivors of the Mau Mau insurgency against British occupation in Kenya have taken their case to the High Court in London.

The first case was won last year when the high court ruled that there was "ample evidence … that there may have been systematic torture of detainees during the [Mau Mau] emergency".

The court opined it would be "dishonourable" for the courts to accept the Foreign and Commonwealth Office's argument that the Kenyans should be suing their current government.

The FCO is now saying the case should be dismissed as too much time has passed since the alleged crimes and a fair trial is not possible anymore.

But lawyers for the veterans say that the discovery last year of thousands of secret FCO files that document the torture and murder of detainees by colonial officials means that the case can be heard.

They argue that the case could not have been brought earlier due to the attempted cover-up and destruction of key documents by FCO officials.

Caroline Elkins, a Pulitzer prize-winning historian, submitted a statement on behalf of the claimants, saying that the destruction of the documents was “an explicit effort to shape an archival record and British colonial legacy in Kenya".

Elkins said, once access to the remaining files was granted, it became clear that torture was sanctioned by Whitehall officials and colonial administrators in Nairobi.

The documents show that British officials were aware of rape, torture and executions, even of children, said The Guardian on Monday:

One letter from 1953 shows that the colony's attorney general, Eric Griffith-Jones, expressed concern that the treatment of detainees was "distressingly reminiscent of conditions in Nazi Germany or Communist Russia".

Despite this, he drafted legislation that sanctioned a form of beatings known as "dilution technique", and then warned the then governor,Evelyn Baring, of the need for complete secrecy, because "if we are going to sin, we must sin quietly."