UK's Hague faces suit over Pakistan drone strikes LONDON (Reuters) - Lawyers for the family of a man killed in a U.S. drone attack in Pakistan said they would begin legal action against Britain's Foreign Secretary William Hague on Monday, accusing him of complicity in strikes they say broke international laws. London law firm Leigh Day & Co said it had "credible, unchallenged" evidence that Hague oversaw a policy of passing British intelligence to U.S. forces planning attacks against militants in Pakistan. It plans to issue formal proceedings against Hague at the High Court in London on behalf of Noor Khan, whose father was died in a drone attack last year. Malik Daud Khan was part of a local "jirga," or council of elders holding a meeting in the tribal areas of northwest Pakistan when a missile fired from the drone hit the group, the law firm said. Attacks by pilotless U.S. aircraft have become a key weapon in President Barack Obama's counter-terrorism strategy in Pakistan and officials say they have helped to weaken al Qaeda's leadership in the region. However, the attacks have become a source of friction between Washington and Islamabad and have angered many Pakistanis who see them as a breach of their sovereignty and the cause of frequent civilian deaths. Leigh Day & Co will argue that those involved in armed attacks can only claim immunity from criminal law if they are "lawful combatants" taking part in an "international armed conflict." Khan's lawyers will say that staff working at UK Government Communications Headquarters (GCHQ) in southwest England, Britain's main intelligence monitoring centre, may have broken the law. As civilians, they are not classed as combatants and could be prosecuted, the law firm said. They will also say that Pakistan is not involved in an international conflict. "There is credible, unchallenged evidence that (Hague) is operating a policy of passing intelligence to officials or agents of the U.S. government and that he considers such a policy to be in 'strict accordance' with the law," Richard Stein, head of human rights at Leigh Day, said in a statement. If this is the case, the Secretary of State has misunderstood one or more of the principles of international law governing immunity for those involved in armed attacks on behalf of a state. A Foreign Office spokesman said it did not comment on ongoing legal proceedings. Asked whether Britain helps the United States in drone attacks, the spokesman added: "We don't comment on intelligence matters." A key ally of Washington in neighboring Afghanistan since the 2001 U.S.-led invasion, Britain has around 9,500 soldiers in the country. The deaths of six British soldiers in southern Afghanistan on Tuesday brought the British death toll to more than 400. Reporting by Peter Griffiths; Editing by Ben Harding