When George W. Bush declared war on terrorism, he pitted a sovereign state against a concept and sent national armies to fight in the borderless territory of ideology. The subsequent three years turned those tables: countries have had to recognise that some of their citizens belong on both sides of the battleground, while terrorists have exploited people’s traditional ties to individual countries. Citizenship laws of the early 20th century were intended to avoid such dilemmas, which are now symbolised most vividly by the case of Margaret Hassan, the aid worker now believed to have been murdered by her kidnappers in Iraq.

Irish by birth, British by upbringing, Iraqi by marriage and a world citizen by virtue of her commitment to the poor, Hassan was stranded for weeks between the countries whose passports she carried. Although she lived in Iraq for 30 years, converted to Islam and, according to her husband, considered Iraq her “native land”, she was British as far as her captors were concerned - and, living as an Iraqi outside Baghdad’s fortified Green Zone, an easy target. Thus, while her fellow Iraqis protested her kidnappers’ actions, Hassan made video pleas to her fellow Britons. Her family, in efforts to help, even offered a third way of classifying her: “She is Irish, not British,” her husband said. In the end, none of it mattered.