The failure of Scottish policing bodies to record the ethnicity of arrested people it takes DNA samples from means there is no way of establishing whether minority groups are over-represented in policing databases, warns Scottish biometric commissioner Brian Plastow.
Following a Joint Assurance Review into the use of DNA for criminal justice and policing purposes, Plastow published a report with his findings on 26 February 2025, which noted the failure of both Police Scotland and the Scottish Police Authority’s (SPA) Forensics Service to suitably record the ethnicity of those it retains DNA for is “concerning”.
He also found that Police Scotland does not have a clear strategic roadmap setting out what it hopes to achieve with DNA or other biometric data and technologies, and questioned the “extraordinarily long retention periods” for DNA data (which Police Scotland can retain until at least a person’s 100th birthday or three years after their death, whichever comes sooner).
Plastow said that while publicly available information on the UK’s National DNA Database (NDNAD) allows observers to see if any ethnic group is over-represented when it comes to their DNA being taken and stored, this is not possible with the Scottish DNA Database (SDNAD), as it does not record any details about a person’s ethnicity.
“We have carried out a detailed review into the use and retention of DNA for criminal justice and police purposes in Scotland, and during our fieldwork, the Scottish Police Authority Forensic Services and Police Scotland were unable to provide us with any reliable management information on the ethnicity of anyone held within the Scottish DNA Database, as the database is nearly 30 years old and was not designed to record this information,” he said.
“The fact that SPA Forensic Services and Police Scotland are failing to properly record and publish data on the ethnicity of arrested people whose biometric data is then held is concerning, against the context of the former and current chief constables having stated publicly that issues of institutional racism persist within Police Scotland.
“Accordingly, we have been unable to establish whether there is any over-representation on the grounds of ethnicity or any other protected characteristic in Scotland.”
He added that properly recording such information, would support Police Scotland’s equality duties, as well as help maintain public confidence and trust.
Data in the UK NDNAD shows that black people in the rest of the UK are significantly over-represented, as while they account for 7.5% of the database entries, they make up just 4% of the overall population, according to the 2021/22 census.
While 1.3% of the population said they were of black heritage in the 2022 Scottish, there is no way of knowing what percentage of DNA samples in the SDNAD have been taken from this group.
Although Plastow’s review report noted that DNA only helps solve only a small number of crimes in Scotland each year (0.34%), these are likely to be the most serious types of crime.
“DNA is not used routinely in police investigations. It is usually only a feature of crimes such as murders, serious assaults, housebreakings and sexual offending,” he said, adding that while DNA provides few investigative leads, those leads can be “spectacular” in their results: “It is not possible to determine how many crimes DNA helps solve in Scotland; however, it will most probably be fewer than 1,000 crimes each year.”
In his recommendations, Plastow said that Police Scotland should review its procedures for recoding the ethnicity of people whose biometric data is held on the SDNAD following arrest, “with a view to fully recording and publishing such data in support of equality duties and to promote public confidence”.
Given the lack of a clear biometric data or technology strategy in the force, Plastow also recommended that Police Scotland – in conjunction with the SPA Forensics Service – should complete the development of a documented strategy outlining its biometrics plans over the next three, five, or 10-year period.
“The plan should be approved by the Force Executive and the Scottish Police Authority and be in place by no later than 31 October 2025,” he wrote.
Writing about the DNA retention period, Plastow said: “It is recommended that in developing a new retention policy, Police Scotland and the Scottish Police Authority should discontinue the blanket practice of retaining the DNA of persons beyond average life expectancy in Scotland in circumstances where they are admonished or given an absolute discharge under summary procedure, providing that they have no previous convictions.”
He added that while an admonishment or absolute discharge under summary procedure are technically convictions, “it would seem more proportionate to the commissioner for the retention period of such data to be aligned with prescribed retention periods for direct measures such as recorded police warnings”.
Computer Weekly contacted both Police Scotland and the SPA about Plastow’s report.
“The Authority welcomes publication of the Biometric Commissioners report which provides important insight to inform the Authority’s oversight of policing and Forensic Services in Scotland,” said an SPA spokesperson. “We look forward to considering the report and recommendations in detail and hearing from the Commissioner himself at a Forensic Services Committee in May.”
Assistant chief constable Steve Johnson of Police Scotland added: “We appreciate the Scottish Biometrics Commissioner’s thorough and detailed review and recommendations into our collection, use and retention of DNA data. We will consider the recommendations in full and with a view to both appropriateness and proportionality, working with SPA Forensic Services.
“Some of the recommendations are already being progressed, for example, a review of our retention periods and the benefit of upgrading lower standard DNA profiles. Ethnicity data is recorded on our Criminal History System, we will consider the proportionality of aligning this and our collection of biometric data.”
In January 2024, Plastow previously warned that Scotland risked “sleepwalking” into a surveillance state that places every citizen in a permanent digital line-up if it does not deviate from the UK government’s then-data reform plans in 2024.
While the UK government under Labour has dropped those plans in favour of a new data reform bill, Plastow described the situation at the time as “a Biometric Wild West where police forces are doing whatever they want”.
He added that the UK government was using “moral panic” around, for example, migration and shoplifting to justify greater levels of surveillance, and that his fears around bulk surveillance have crystallised in recent months due to the actions of government ministers.
This included a proposal from then-policing minister Chris Philp, who called in October 2023 for data from the police national database (PND), the Passport Office and other national databases to be integrated with facial-recognition technology to help catch shoplifters and other criminals with the “click of one button”.
Responding to Philp’s proposals at the time, Plastow said he viewed “this egregious proposal as unethical and potentially unlawful”, and further condemned it “as a gross violation of British privacy principles”.