Digital Evidence on Trial: What the Danish Telecoms Scandal Teaches Us About Trust, Governance and Justice
Steve Rick, CEO, Forensic Analytics.
The Danish “telecom scandal”1 is one of the most significant modern examples of digital evidence failures in criminal justice and is highly relevant to any discussion about evidential standards, accreditation, and quality assurance for digital forensic data.
What happened?
In 2019, Danish authorities discovered serious errors in the processing of telecommunications data that had been used as evidence in criminal investigations and court proceedings for many years. The problem was not primarily that mobile network data itself was wrong, but that the systems and processes used to convert, analyse and present that data introduced errors.
The issues reportedly included:
Data being lost during conversion from telecom provider records.
Mobile phones being associated with incorrect cell towers.
Some cell tower location information being incorrect.
Errors affecting the interpretation of SMS location data.
Weaknesses in quality management and validation processes.
As a result, the Danish Director of Public Prosecutions imposed a temporary moratorium on the use of telecoms data in criminal proceedings, and the scandal led to:
Reviews of thousands of cases.
New requirements for quality control and evidential disclosure
How many cases were affected?
Different sources cite slightly different figures, but the review covered approximately 10,700 cases dating back to around 2012. Danish prosecutors and courts suspended or restricted the use of certain telecom evidence while the issue was investigated. Dozens of prisoners were reportedly released pending review of their cases.
Why is this important?
The scandal demonstrated several key lessons:
Digital evidence is not inherently reliable simply because it is computer-generated. Courts had treated telecom data as highly objective evidence, but the investigation showed that interpretation and processing can introduce significant error.
Quality management matters as much as technology. Academic reviews of the scandal concluded that the failures were socio-technical, involving people, processes, competence, governance and quality assurance, not just software defects.
Validation and accreditation are essential. The case is now frequently cited internationally as an example of why methods used to extract, process and interpret digital evidence must be independently validated and subject to ongoing quality control.
Relevance to UK and International Policing and Forensic Analytics
From a UK forensic science perspective, the Danish case is a powerful illustration of why:
ISO/IEC 17025-accredited methods matter.
Evidence provenance and audit trails are critical.
Software outputs should not be accepted as "black box" truths.
Investigators and prosecutors need to understand the limitations and uncertainty associated with digital evidence.
It aligns closely with the arguments I’ve been developing in When Compliance Becomes Strategy that assurance of digital evidence requires not just technical capability, but demonstrable governance, validation, competence and transparency throughout the evidential lifecycle.
The Danish telecom scandal was not a failure of telecommunications data. It was a failure of evidential governance. More than 10,000 criminal cases had to be reviewed because the processes used to transform data into evidence lacked sufficient quality assurance. The lesson for policing is clear: digital evidence is only as trustworthy as the systems, standards and people that produce it.
The Danish along with the UK Horizon scandal examples are particularly persuasive when thinking about and or discussing accreditation, evidential integrity and public trust because it demonstrates the real-world consequences when those controls fail.
Sources:
The use of Historical Call Data Records as Evidence in the Criminal Justice System: Lessons Learned from the Danish Telecom Scandal. Authors: Lene Wacher Lentz and Nina Sunde. Published in Digital Evidence and Electronic Signature Law Review (2021)