Home Office slams PNC tech team: 'Inadequate testing' of new code contributed to loss of 413,000 records

Poorly defined business requirements, failure in documentation, independent report finds

An independent review of a technology failure that led to the loss of 413,000 records of evidence from the UK’s Police National Computer (PNC) has found a lack of reviews and effective testing contributed to the debacle.

Although the lost data has all been recovered, according to Kit Malthouse, minister for crime and policing, an independent investigation into the incident, led by Lord Bernard Hogan-Howe, has found that established procedures, such as reviews, were only loosely followed or in some cases not followed at all, during the introduction of the faulty script. Hogan-Howe is a former head of London's Metropolitan Police.

The incident, which left Prime Minister Boris Johnson floundering in Parliament in February, was the result of a scripting error in code designed to weed out records to be deleted from the PNC, a 43-year-old system running on a Fujitsu BS2000/OSD SE700-30 mainframe-based at a data centre in Hendon, London.

The team introducing the code did not have fully defined business requirements and was not maintaining an accurate record of tests undertaken, the report found.

Meanwhile, there was a failure to "design effective and complete tests, including for affected systems, and what appears to be a significant failure of the manager whose responsibility it was to thoroughly review the testing procedures prior to approval. It appears this was not done," the report said.

"Testing of the new code was inadequate and specific processes within the change were not tested at all. It is concerning that the supporting documentation for these recent actions cannot be found," according to the report, produced on 19 March.

Also among the criticism was an apparent cosiness among the ageing PNC’s operational team. "The team who operate it have worked together over a long period of time. The expertise and closeness of the teams involved in running the PNC increased the risk that their work would be accepted rather than checked by a leadership that were in a poor position to challenge their decision making. The PNC services team has very limited police experience in the team and have limited understanding of how the police operate," the report said.

However, the report said the age of the PNC should be considered. Its replacement, the National Law Enforcement Data Programme (NLEDP), which enables the decommissioning of PNC, is undergoing a fundamental reset, although some projects in the programme were meant to have gone live last year.

According to a review of Home Office systems submitted to Parliament NLEDP “is progressing against its new plan and is looking to deliver incrementally so that PNC and [Police National Database] can be decommissioned during 2022 and 2023 respectively."

As such, investment in the PNC should not be ignored, Lord Hogan-Howe's report [PDF] said. The Home Office should create a plan, with investment, to sustain PNC for its full life.

"Within 8 weeks, the Home Office must provide the Police with feasibility options, including estimated timescales, costs and risks for either replacing or sustaining the PNC," the report said.

Other recommendations include introducing PNC user representatives to help oversee developing and running the PNC, making a technical architect responsible for the end to end technical design system, and creating product management lifecycle techniques for the PNC service. ®