As much as the Home Office has always insisted that safeguards are in place, its interest in the records of migrants using the NHS has long been highly controversial. True to form, government spokespeople say “There’s nothing to see here” when asked about the move – made with no fanfare – to order the NHS to input a Home Office reference number into the records of “relevant patients”. The measure, insist government sources, is to “improve” the collection of a Home Office initiative known as the immigration health surcharge, which charges for use of the NHS. Yet it is the potential future use of the reference number that has once again alarmed trade unions, campaigners and others who previously forced the scrapping of a “hostile environment” scheme using NHS data to track down patients. Home Office interest in medical records dates back to Theresa May’s tenure as home secretary as the government stepped up its drive to “create a hostile environment” for illegal immigrants. A memorandum of understanding, signed in secret and published months later in 2016, made it clear that NHS Digital – now dissolved but at that time a data-gathering branch of the NHS – was required by law to hand over non-clinical patient details including last known addresses, dates of birth, GP’s details and date registered with doctor. In the year up to the publication of the deal, the confidential patient records of more than 8,000 people were handed by the NHS to the Home Office, whose requests were increasing. The deal followed a similar agreement between the Home Office and the Department for Education (DfE) to share the details of up to 1,500 pupils a month to trace potential immigration offenders. That memorandum, only released after several organisations made a freedom of information request, revealed that the DfE the would share pupils’ names, recent addresses, school and some attendance records, including earliest and latest attendance dates. However, in May 2018 the government suspended the data-sharing agreement between the NHS and Home Office in the face of warnings by doctors’ groups and health charities that the practice was scaring some patients away from seeking NHS care for medical problems. Seven months later a court challenge brought by the Migrants’ Rights Network led to the memorandumbeing scrapped. Since then, concerns about the consequences of treating some users of the NHS differently from others appear to have been vindicated on at least one occasion. In 2021, a report found that Lewisham and Greenwich NHS trust’s approach to charging “overseas” patients for healthcare may have scared people away from seeking treatment, prompting an apology from the trust. It is against this background that organisations such as Liberty, which was instrumental in getting the 2016 memorandum thrown out, want clarity, not least in an age of increasing digitisation of NHS and other records. “The government must once and for all commit to dismantling the hostile environment and implement a data ‘firewall’ – a cast-iron promise that personal information collected by trusted services will not be shared with the Home Office for immigration enforcement,” Sam Grant, Liberty’s advocacy director said.