Foreign Secretary William Hague will be in court tomorrow over Britain's alleged support for illegal CIA drone attacks in Pakistan.
Britain reportedly provides intelligence for the strikes - a practice now being challenged by Pakistani Noor Khan, whose father was killed in a drone strike on a local jirga (council meeting) in Waziristan last year.
Malik Daud Khan, a tribal elder, was one of more than 40 people killed when a missile fired from an unmanned drone hit the open-air meeting at Datta Khel on March 17 2011.
Mr Khan has asked Mr Hague to spell out the government's position and challenged the legality of such intelligence sharing for strikes.
US attempts to kill "militants" in Pakistan through its secretive robotic air war have claimed the lives of hundreds of civilians.
Mr Khan is being supported by legal action charity Reprieve and represented by solicitors Leigh Day & Co.
Reprieve legal director Kat Craig said: "Drones in Pakistan hover over towns 24 hours a day, seven days a week, terrorising communities and killing innocent civilians.
"Neither we, nor the communities affected, know who is considered a target, nor how that process is decided.
"Noor Khan merely wishes to know what role the British intelligence services play in this game of one-sided Russian roulette.
"He is calling for the veil of secrecy around Britain's drones policy to be lifted so that he can keep his community safe."
Rosa Curling of Leigh Day & Co said: "This case is about the legality of the UK government providing 'locational intelligence' to the US for use in drone strikes in Pakistan.
"An off-the-record GCHQ source stated to a number of media outlets that GCHQ assistance was being provided to the US for use in drone attacks and this assistance was 'in accordance with the law.'
"We have advised our client that this is incorrect.
"The Secretary of State has misunderstood the law on this extremely important issue and a declaration from the court confirming the correct legal position is required as a matter of priority."