A UK court has blocked a lawsuit against the British government for participating in U.S. drone strikes on the grounds the case would make the U.S. look bad.

Twenty-eight year old Noor Khan sought accountability from the UK intelligence agency GCHQ for its role in a CIA drone strike on a local council meeting in North Waziristan that killed his father, a local elder, in 2011.

Khan brought the case against the UK government upon evidence that GCHQ has been aiding the CIA’s covert drone war in Pakistan.

According to human rights charity Reprieve, Khan’s lawyers charged that the UK’s participation in the drone campaign is illegal and could result in murder charges for UK officials.

Yet Khan was told by London’s Court of Appeal on Monday that the case cannot continue because “the court would have to find the CIA implicitly guilty of a war crime before it could consider whether GCHQ had been involved,” according to a Guardian summary of the ruling.