The High Court is to rule on a plea to end 63 years of "obstruction and refusal" by successive UK governments to investigate fully a "massacre" of Malaysian rubber plantation workers by British troops.
In May, lawyers representing relatives of victims said that there was now enough evidence to justify an independent inquiry into the "war crime" killings of 24 unarmed workers.
The families see an inquiry as the first step to eventually obtaining an apology and reparations.
The incident, involving a platoon of Scots Guards, happened on December 12, 1948, while British troops were conducting military operations to combat the post-Second World War communist insurgency known as the Malayan Emergency.
Soldiers surrounded the rubber estate at Sungai Rimoh in Batang Kali and shot dead 24 people before setting light to the village.
Michael Fordham QC said that the incident was "a blot on British colonisation and decolonisation" and asked the court to overturn the current Government's refusal last November to hold a formal investigation.
Foreign Secretary William Hague and Defence Secretary Philip Hammond have jointly resisted the application for judicial review, arguing that the decision not to hold any form of inquiry was reached lawfully.