From messy data to meaningful connections: Introducing Splink 5

16 Oct 2026 12:12 PM

Blog posted by: Robin Linacre, 15 October 2026 – Data, Our services, Splink.

We are excited to introduce Splink 5, the latest version of the Ministry of Justice's open-source software for linking records across datasets.  

Developed to tackle some of government's most complex data-linking challenges, Splink has grown into a tool used across the UK public sector and around the world. 

Across large organisations, information about the same person can be spread across multiple systems, duplicated, incomplete or inconsistent. Connecting those records accurately is essential for delivering better services, better research and better decision-making. 

That's where Splink comes in. 

Splink helps organisations identify records that belong to the same person or entity, even when the underlying data is messy or inconsistent. For example, someone's name may be spelled differently across two systems, they may have changed address, or one record may contain a typo. 

While this might sound like a niche challenge, it is something almost every large organisation encounters. Accurately linking records improves data quality, reduces duplication and helps organisations make better use of their data. 

That's one reason Splink has seen substantial adoption across the public sector, with more than 22 million downloads and use across at least 10 central government departments and agencies.  

What Splink 5 brings to the table 

Splink 5 is our biggest step forward yet, making it easier to link data at a scale that was previously difficult or impossible for many organisations. 

The new release can handle substantially larger datasets and is now one of the fastest linkage engines in the world. In our testing, Splink linked a billion records in less than 10 minutes, helping organisations turn vast amounts of data into meaningful insights more quickly than ever  

Detailed release notes for Splink users can be found here 

Impact across the justice system 

Within the Ministry of Justice, Splink plays a vital role in bringing together information from courts, prisons and probation services. By connecting data that would otherwise remain fragmented across multiple systems, it helps create a more complete understanding of people's interactions with the justice system. 

The technology powers JustLink and supports the Data First research programme, enabling richer analysis of court outcomes, offending patterns and journeys through the justice system. It also sits at the heart of Core Person Record and is beginning to give frontline prison and probation officers more timely and accurate linked data. 

A home-grown tool with a global footprint 

Built to solve justice-system challenges, Splink is now delivering impact far beyond the Ministry of Justice and is used widely 

Recent use cases include: 

The Australian Bureau of Statistics won a public sector award for their work using Splink to build the 2025 National Linkage Spine 

• University of Cambridge used Splink to perform the first full-count linking of historical English and Welsh censuses (1851-1921) 
• NHS England has gone live with a new data linkage model using Splink as the core engine for a new probabilistic data linkage service 
• South Africa's National Cancer Registry and National Health Laboratory Service used Splink to enable population-scale research into cancer incidence and cancer care among people living with HIV 

Try it out for yourself

Splink 5 is entirely free, open source, and available to anyone right now. 

What started as a solution to some of the Ministry of Justice's most complex data-linking challenges is now helping organisations across government, academia and beyond connect data with greater accuracy and confidence. 

• Learn more: Visit the Splink documentation to read the release notes and try interactive tutorials directly in your web browser. 
• Explore the code: Check out the project on GitHub. 
• Get in touch: If your team has a data linking challenge, or if you are already using Splink and want to share your experience, we would love to hear from you at DataLinkingTeam@Justice.gov.uk

From supporting justice services to enabling research around the world, Splink is helping organisations turn messy data into meaningful connections.