Annual review of GPS tagging in the immigration system, 2023

Government doubles down on experimental surveillance tech to track migrants

Constantly on Edge’, the latest report on GPS tagging in immigration bail, has found that the Home Office has increased its use by 56% in the last year and is now using newer, experimental mobile fingerprint scanners to monitor migrants on bail, without effective safeguards in place.

Users of the new ‘non-fitted’ scanner devices – supplied to the Ministry of Justice by Buddi under a £6 million contract – described the experience as a “type of torture” and spoke of feeling “constantly on edge”.

The research comes a year after Public Law Project, Bail for Immigration Detainees, and Medical Justice published ‘Every move you make’ which revealed the ‘psychological torture’ caused by fitted GPS tracking devices.

Interviewees told researchers that the newer, non-fitted devices vibrate up to 10 times a day at random intervals, sometimes into the evening. If users are unable to scan their finger within a window of ‘around a minute’, they are considered to be in breach of their electronic monitoring bail condition. That breach is then reviewed by the Home Office.

Researchers found that an automated system – the Electronic Monitoring Review Tool (EMRT) – is used to decide which device type will be issued and for how long the person will be required to use it. Authors Dr Jo Hynes and Mia Leslie of the Public Law Project say there is not enough transparency around how the EMRT works to be sure that the process is free of bias.

The report found that reviews of decisions to impose GPS devices – a key safeguard in the process – are not being conducted in sufficient volumes.  As of July 2023, 622 quarterly reviews were overdue.

Author of the report Dr Jo Hynes said:

“These devices are utterly dehumanising. It is hard to imagine the vigilance required to be ready to scan your finger immediately at random times throughout the day, or risk  breaching your bail conditions. Our interviews with migrants show how oppressive this system is and the impact that constant watchfulness has on their daily lives and wellbeing.

“This level of surveillance is not only harmful, it is unnecessary. The rate of absconding from immigration bail is tiny. In 2021 it was 2.7% and in the first six months of 2022 it was 1.3%. Millions are being spent on a system to address a problem that is not evidenced, and which causes psychological harm to people already made very vulnerable by Home Office policies.

“With a pilot study having recently concluded, it seems likely that Government may look at rolling these devices out to people who arrive by ‘irregular’ means i.e. by small boat. Given what we know about the potential harm these devices can cause, such a move would be highly inappropriate.

“The systems around this surveillance regime are opaque and dysfunctional. There is limited transparency around the automated decision support tool used to decide which device type will be issued and for how long the person will be on it. In addition, in breach of its own guidelines, the Home Office has a significant backlog of reviews to complete, leaving many at risk.”

Testimony from people interviewed for ‘Constantly on edge’

Interviewees taking part in the research who have been required to use the non-fitted devices report feeling “constantly on edge” and “like a lower type of human”. Another described it as “a type of torture”.

“If you have to go to the bathroom or to use the toilet, everywhere that thing’s with you.” – Interviewee

“I felt like someone is always following me, behind me. It’s like, imagine you’re walking outside and someone is like walking behind you. Following you, like wherever you go that person is following you. You will start to panic. You shouldn’t be harming the person you are watching. That is really very bad, like I said, being watched is horrible.” – Interviewee


‘Constantly on edge’ was written with the support of Bail for Immigration Detainees (BID) and Medical Justice.

Pierre Makhlouf, Legal Director of BID, said:

“GPS tagging is a punitive measure that is unnecessary and generates fear of authority. Its use is disproportionate, entailing 24-hour surveillance and control of individuals, while being supported by policies that interfere with an individual’s right to privacy. Its use needs to be ended now.”

Emma Ginn, Director of Medical Justice said:

“Having already established that electronic monitoring carries a high risk of causing deterioration in existing poor mental health, Medical Justice is saddened that the Government has significantly increased its use. Reports of severe detrimental effects on mental health, including to the point of suicidal ideation, therefore come as no surprise.

“Many of our clients have experienced immense suffering before they reached the UK and are retraumatised by immigration detention here. Being tagged on release can impede their recovery.  Though they may have left detention, intense surveillance and control continues, with the associated risk of harm.”


Key findings:

  • In 2023, there has been a 56% increase in the number of people GPS tagged as a condition of immigration bail.
  • Non-fitted tagging devices were introduced from November 2022. These fingerprint scanner devices request periodic biometric verification from the user (vibrating at random times) and collect the person’s location data at all times.
  • Between 1 January 2023 and 2 November 2023, 3,335 people have been subjected to fitted devices and 543 people subjected to non-fitted devices as a part of an electronic monitoring bail condition.
  • Reviews of decisions to impose a GPS tag (a key safeguard) are not being conducted in sufficient volumesAs of July 2023, 622 quarterly reviews were overdue.
  • An automated system – Electronic Monitoring Review Tool (EMRT) – is used as part of the process for deciding which device type people will be subject to, if they should be moved from a fitted to a non-fitted device, or if their monitoring is to be discontinued.
  • The extent of the EMRT’s role in decision-making is opaque, making it difficult to assess the extent of automation bias in the decision-making process.
  • The length of advised time people spend on devices is vast, ranging from 3-24 months on a fitted device to 18 months to indefinitely on a non-fitted device
  • Buddi Limited was given £6 million to make these devices. The contract comes to an end on 30 December 2023.