People trafficked to Syria and radicalised remain threats to national security as they may be desensitised after exposure to extreme violence, the Home Office has argued, in contesting Shamima Begum’s appeal against the removal of her British citizenship. Begum was 15 when she travelled from her home in Bethnal Green, east London, through Turkey and into territory controlled by Islamic State (IS). After she was found, nine months pregnant in a Syrian refugee camp in February 2019, the then home secretary, Sajid Javid, revoked her British citizenship on national security grounds. Begum, now 23, is challenging the decision at the special immigration appeals tribunal (Siac). The tribunal heard that according to the security services, people who travelled to Syria to align with IS “were likely to have been radicalised, to have contributed to the continuance of [IS] as an entity and may have received military training, fought with [IS] or taken part in terrorist attacks”. “They were exposed to routine acts of extreme violence, which would be likely to have had the effect of desensitising individuals and encouraging them to view violent terrorist activity as an ‘acceptable and legitimate course of action,’” the court in London was told in written submissions on Thursday. Sir James Eadie KC, for the Home Office, said Begum spent four years in IS-controlled territory before the removal of her citizenship. He later referenced statements that she has made to the media, including an interview in which she said she was not fazed about seeing a head in a bin. “If you have been exposed for prolonged periods, there is an almighty problem,” Eadie said. Begum’s lawyers have said she was “recruited, transported, transferred, harboured and received in Syria for the purposes of sexual exploitation and marriage to an adult male”. Eadie said the threat posed to national security was the most important factor. “You can be trafficked in the most ghastly, unacceptable way, exposed in the most unacceptable way, desensitised in the most unacceptable way, and yet unfortunately … still be a security threat.” Begum’s lawyers argued she was “persuaded, influenced and affected with her friends by a determined and effective Isis propaganda machine”. Samantha Knights KC said in written submissions: “What evidence is available shows that rather than viewing the appellant as a victim, a child that was manipulated and exploited, the home secretary proceeded on the basis that she acted ‘voluntarily’ in travelling to Syria and aligning with Isis.” The hearing, before Mr Justice Jay, is due to finish on Friday, with a decision expected in writing at a later date.