LONDON — The letter informing Mohamed Sakr that he had been stripped of his British citizenship arrived at his family’s house in London in September 2010. Mr. Sakr, born and raised here by British-Egyptian parents, was in Somalia at the time and was suspected by Western intelligence agencies of being a senior figure in the Shabab, a terrorist group linked to Al Qaeda.
Seventeen months later, an American drone streaked out of the sky in the Lower Shabelle region of Somalia and killed Mr. Sakr. An intelligence official quoted in news reports called him a “very senior Egyptian,” though he never held an Egyptian passport. A childhood friend of Mr. Sakr, Bilal al-Berjawi, a Lebanese-Briton also stripped of his citizenship by the British government, was killed in a drone strike a month earlier, after having escaped an attack in June 2011.
Senior American and British officials said there was no link between the British government’s decision to strip the men of their citizenship and the subsequent drone strikes against them, though they said the same intelligence may have led to both actions.
Britain, along with Israel, is one of the few countries that can revoke the citizenship of dual nationals — even if they are native born — if they are suspected or convicted of terrorist offenses or acts of disloyalty.
Britain is seeking to expand the practice to naturalized citizens who have no other nationality and would be rendered stateless. Citizenship, in the words of Home Secretary Theresa May, is a “privilege, not a right.”
The issue is beginning to stir public debate. A government-sponsored amendment expanding the practice to naturalized citizens who have no other nationality sailed through the House of Commons this year. But on Monday, in a rare act of parliamentary rebellion, the House of Lords rejected the amendment and asked instead for a joint committee of both houses to examine whether the additional powers are necessary. The draft legislation will now return to the House of Commons.
Britain typically strips people of citizenship when they are outside the country. The procedure requires only that the home secretary find that stripping someone of citizenship would be “conducive to the public good,” then sign a deprivation order and send a letter to the person’s last known address. Loss of citizenship is effective immediately. It can be challenged in court, but that is a difficult task in most cases, given the inability of a targeted person to return to Britain for any proceedings.
Mr. Sakr, who was killed in February 2012, had appealed on the grounds that the British government was rendering him stateless. He had never sought an Egyptian passport despite being eligible for one because of his parents’ heritage. He eventually abandoned his appeal for fear that frequent communication with his lawyer on a cellphone or computer would make him vulnerable to a drone strike by giving away his location, according to his lawyer at the time, Saghir Hussain.
Mr. Berjawi was killed in January 2012, hours after using a cellphone to call his wife in a London hospital on the day their son was born.
In a case involving the United States, a Somali-born Briton, Mahdi Hashi, was stripped of his British citizenship in June 2012 and then captured and detained on an American base in Djibouti two months later. He was taken to the United States, where he awaits trial on terrorism-related charges.
“The sequence of events does not look accidental,” said Mr. Hussain, who is also representing Mr. Hashi in a separate appeal against his deprivation order.
Forty-two people have been stripped of their British citizenship since 2006, 20 of them last year, according to a freedom of information request filed by the Bureau of Investigative Journalism, a research organization at City University London that first drew attention to the practice in December 2012. In Israel, by comparison, the power to revoke citizenship has been used only twice since 2000, according to the Interior Ministry there.
Hilal al-Jedda, an Iraqi-born, naturalized Briton, lost his British nationality in 2007 after being detained in Iraq on suspicion of smuggling explosives.
Out of 15 appeals, his is the only one to have succeeded. Britain’s Supreme Court ruled in October that Mr. Jedda could not be deprived of his British nationality because it would make him stateless: Iraq bans dual citizenship and canceled Mr. Jedda’s passport in 2000 when he was naturalized in Britain. The British government was forced to reinstate his citizenship on Oct. 9, 2013.
But on Nov. 1, Mr. Jedda was stripped of his nationality a second time, and in January the Home Office rushed the amendment before Parliament allowing deprivation even if it results in statelessness, provided that a suspect’s citizenship is “seriously prejudicial to the vital interests of the United Kingdom.”