The death of Malik Daud Khan, a Pakistani tribal elder, in a C.I.A. drone strike might have remained widely unremarked upon, lost amid thousands of others analysts have tallied in the American drone campaign, had not the British courts been brought into it.

The drone strike, which killed Mr. Khan and dozens of others at a tribal council meeting in North Waziristan in 2011, spawned a lawsuit that accuses British officials of becoming “secondary parties to murder” by passing intelligence to American officials that was later used in drone strikes.

The case has put a spotlight on international intelligence-sharing agreements that have long been praised by officials as vital links in the global fight against terrorist groups, but that rights advocates criticize as a way for Britain and other European countries to reap the benefits of the contentious drone program without its political costs.

Judges in Britain have yet to decide whether to hear the case, brought forward by Mr. Khan’s son, Noor Khan, a British citizen. (They initially declined, but are considering an appeal that was lodged in January.) It has caused a particular sensation, though, because it raises the prospect of legal liability for European officials by linking them to an American drone campaign that is widely seen as publicly unpalatable, or simply illegal, in their home countries.