An anthropologist who travelled with a British woman who took her life at Dignitas is suing the police after she was arrested upon her return on suspicion of encouraging suicide. Miranda Tuckett, who is researching a doctoral thesis on Britons going to Switzerland to take their own lives, is bringing a high court claim for damages against Dyfed-Powys police for false imprisonment, breach of her academic freedoms and assault and battery. She was arrested in London by four police officers and driven through the night to a police station in Wales, where she was held in a cell for 11 hours before a six-month investigation. The case has embroiled the prime minister, Keir Starmer, who intervened to try to persuade the police to let Tuckett go in his capacity as a constituency MP. The subject she was studying, Sharon Johnston, 59, had been paralysed in a fall and decided to take her own life because she didn’t want to rely on constant care. Tuckett travelled to Switzerland with her as part of her PhD research at a New York university. Police gathered evidence from a taxi company, CCTV from Johnston’s care home and national traffic cameras, then arrested Tuckett on suspicion of assisting suicide, which is punishable by up to 14 years in jail. Late in the evening on 15 February 2022, after she returned from Zurich, where she had seen Johnston take her own life, Tuckett was arrested by four officers in north London. They seized her computer and research materials and drove her five hours through the night to a Welsh police station where she was fingerprinted, held in a cell “incommunicado” and questioned. Dyfed-Powys police had earlier issued a missing persons report when Johnston left her care home, and repeatedly called Johnston while she was en route to Heathrow airport, in the departure lounge and again in Switzerland. Armed Swiss police were sent to the Dignitas facility the day before Johnston was due to die to question her. The police at one point enlisted a trained hostage and crisis coordinator to call, which drew a response from Johnston. She texted her care home manager to say: “IT WAS MY DECISION MY CHOICE I HAVEN’T BEEN INFLUENCED WHATSOEVER.” Tuckett said that after the series of police calls “everything about [Johnston] changed. She had been so light, so happy and then … she closed down. She was stressed and visibly flustered by it. She was hassled by the police. She told me she spoke to them multiple times and said: ‘Stop calling me, I know what I’m doing.’” The police also arrested a second person, Sue Lawford, a supporter of the pro-assisted dying campaign group My Death, My Decision, who accompanied Johnston. Lawford is also suing the police for unlawful arrest, since National Police Chiefs’ Council guidelines state that police should interview anyone suspected of having encouraged or facilitated assisted suicide under caution as a voluntary attender. Instead, she was arrested at 5.30am in Cardiff shortly after returning from Switzerland and held for 19 hours in a police cell, causing “not inconsiderable emotional damage”. The case exposes the inconsistency in police interpretation of UK assisted dying laws, which stems from the tension between NPCC guidance to consider the public interest before taking action, and the fact it is illegal to help end someone’s life in England and Wales and to help them go to other countries to do so. As a result, some people who join loved ones receive no police attention. Equally, people with capacity can travel alone to countries like Switzerland, where the practice is decriminalised. Starmer demanded Tuckett’s immediate release and return to London in his capacity as the constituency MP of her parents, in whose home she was arrested in north London. The then leader of the opposition wrote an urgent letter to Richard Lewis, the Dyfed-Powys chief constable, saying he was “very concerned” at the detention and that on the basis of what he knew “there was no basis for believing that” the case could meet the public interest test in the Crown Prosecution Service’s assisted suicide policy, court documents show. Downing Street declined to comment on ongoing legal proceedings. In opposition, Starmer said he was personally in favour of a law change and promised a free vote in parliament. Dyfed-Powys police pressed on with Tuckett’s arrest despite entries on police logs saying Johnston “had full capacity and can make clear and informed decisions” and “there was no evidence to suggest she was being coerced into her decision-making”. Tuckett claims she sustained psychiatric injury, humiliation and suffering as a result of “arbitrary, oppressive and unconstitutional conduct”. She is claiming aggravated and exemplary damages, alleging the police acted without regard to Starmer’s intervention, delayed progressing the investigation for months and refused to cooperate with the return of her academic research materials, which caused more than a year’s delay to her work. Nathan Stilwell, a spokesperson for My Death, My Decision, said: “The treatment of Sue and Miranda was wrong – indeed, it went against the police’s own guidance at the time. Nobody who acts out of compassion for someone in need should face such drastic consequences. This case highlights why our current law is so barbaric and out of date.” A spokesperson for Dyfed-Powys police said: “In February 2022 two women were arrested on suspicion of encouraging suicide following the death of Sharon Johnston. They were arrested after enquiries were commenced in Cardigan into reports of a female missing from her home. Following an investigation the two women were told they will face no further action in August 2022. Further comment would be inappropriate due to the ongoing litigation.”