We believe in the power of diversity and inclusion, fostering an environment where every individual can grow, thrive, and contribute to our shared success.
Employee-Ownership Trust
Growing together as an EOT
As an employee-owned company and part of the Employee Owner Associated, every team member has a stake in our success. This shared ownership nurtures a collaborative culture, where individual voices are heard, ideas take flight, and innovation blossoms.
Our employees are not just workers; they propel us forward with passion, motivation and investment in Butterfly Data’s success. This translates into exceptional service, best-in-class solutions, and a commitment to excellence that sets us apart in the industry.
Armed Forces Covenant
Supporting the Armed Forces
We are proud to support the Armed Forces community, with Army Reservists contributing valuable skills, leadership, and discipline to our team.
As part of our commitment to reservists, service leavers, veterans, Cadet Force adult volunteers, and military spouses, we’re honoured to have received the Gold Employer Recognition Scheme Award from the Armed Forces Covenant.
As an employee-owned company, every team member has a stake in our success. This shared ownership nurtures a collaborative culture, where individual voices are heard, ideas take flight, and innovation blossoms.
Our employees are not just workers; they propel us forward with passion, motivation and investment in Butterfly Data’s success. This translates into exceptional service, best-in-class solutions, and a commitment to excellence that sets us apart in the industry.
Continuous learning
Nurturing talent
We believe in nurturing growth through mentoring and continuous learning.
Our Graduate Scheme offers a supportive pathway for new talent to spread their wings, while our mentoring program connects experienced employees with mentees to share knowledge, overcome challenges, and foster camaraderie.
Through the Butterfly Academy, we also provide dedicated personal development time for our team, enabling them to pursue courses, workshops, and other opportunities that enhance both professional and personal skills.
By investing in our employees' development, we cultivate an inclusive culture of growth, where everyone can reach their full potential.
What the parliamentary record,government data and two decades of delivery experience reveal about the realprice of standing still when it comes to legacy IT and data systems.
Why legacy data systems are now a public sector priority
For organisations managing national-scale, citizen or mission-critical data, this is not an abstract policy problem. It shapes how services are delivered today, how securely data is held, and how much of the investment now flowing into AI and cloud platforms will actually deliver value.
Key findings
28%
of central government IT estates are classified as legacy, up from 26% in 2023.
State of Digital Government Review, January 2025
22%
of legacy systems are red-rated, indicating known security vulnerabilities, lack of vendor support, or inability to meet current requirements.
State of Digital Government Review, January 2025
3–4×
more expensive to maintain legacy systems than modern alternatives.
House of Commons Science, Innovation and Technology Committee, 2026
228
legacy IT systems identified across government departments as of March 2024.
National Audit Office / NCSC
123
critical outages in NHS England in 2024, some linked directly to patient harm.
State of Digital Government Review, January 2025
30%
less spent on technology by government than international benchmark comparisons.
It sets out the departmental commitments now in the roadmap, from DWP's benefits modernisation to the Home Office's move from the Police National Computer to the Law Enforcement Data Service. It explains the four ways delay compounds cost: the cost spiral, the security risk, the knowledge concentration risk and the blocked opportunity cost.
It also compares legacy dependency across central government, policing, health and local government. It covers security, compliance and vendor lock-in, the seven principles of good migration, and the realities of migrating common platforms such as SAS 9.x, SAP, Oracle and legacy ETL. It closes with three framings that help make the internal case for investment.
Who it is for
Data leaders, transformation teams and technology decision-makers in the public sector and critical data organisations across the UK.
Download the whitepaper
The hidden cost of legacy data systems in UK public services
Complete the form to get the full whitepaper as a PDF and access the interactive web version, including the evidence base, platform guidance and key sources.
Frequently asked questions
How much of UK government IT is legacy?
The State of Digital Government Review (January 2025) found that on average 28% of central government IT estates are classified as legacy, up from 26% in 2023. Legacy estates range from 10% to 70% across police forces and 10% to 50% across NHS trusts. Around 15% of organisations cannot estimate their legacy estate at all.
How much more does legacy IT cost to maintain?
Maintaining legacy systems typically costs three to four times more than maintaining modern alternatives, according to evidence gathered by the House of Commons Science, Innovation and Technology Committee. McKinsey estimates that CIOs put technical debt at 20–40% of the total value of their technology estate.
Why does delaying legacy migration make it more expensive?
Delay compounds cost in four ways. Maintenance costs rise and legacy risk accumulates faster. Unsupported platforms carry known vulnerabilities that cannot be patched. The staff who understand how systems really work retire or move on. And data trapped in legacy formats blocks AI, data sharing and joined-up services.
What is the knowledge concentration risk in legacy migration?
In many public sector organisations, the operational knowledge of a critical platform, including its undocumented logic, workarounds and integration quirks, sits with two or three people who have worked with it for a decade or more. The window in which they can support a structured migration is finite, and every year of delay narrows it.
Where should a legacy migration project start?
The right starting point is a structured discovery engagement, not a migration project. Discovery maps applications, data stores and dependencies, assesses data quality, compliance and security risk, and engages the people who carry undocumented knowledge. It produces the evidence base for a credible migration business case.
How can public sector organisations procure legacy migration support?
Butterfly Data's legacy migration services are available through G-Cloud 15 (Lot 3), other GCA frameworks and the Home Office ACE project. Public sector organisations can procure directly through these routes without a full competitive tender process, which reduces procurement overhead and time-to-engagement.
The data problems you have within your department are probably very apparent. However, the trouble usually lies when it comes to getting those data problems proven.
When asking a data product owner where their data is most at-risk; quite often we are given a list of systems, teams and a rough estimate as to when things started to deteriorate. The assumption is there, but whatever you need to show a finance department for support in resolving the issue most likely does not exist. This is an important difference. A concern stated without some form of evidence (supporting data) will sound similar to an opinion and opinions don't fare too well around budget meetings.
An old problem that hasn't gone away
In a 2019 National Audit Office report on the UK government's use of data, it was found that instead of using available assessment tools to evaluate the overall quality of the data collected by each department, new programs were created that highlighted existing issues. The report noted, "Good data is not a 'free good,'" therefore departments would need to invest resources in obtaining high-quality data on a systematic basis.
The State of Digital Government Review in 2025 also revealed this same picture. Even six years later, it required a significant amount of effort to find rudimentary information regarding risk, cost or service quality.
What working without data maturity assessment can cost you
The costs associated with the lack of evidence tend to become most visible during budget season. Typically money goes to either the person who is the most senior or the one yelling the loudest when there is no agreement regarding what is most important.
Another less obvious expense is repetition. Teams will continue to address symptoms while having little knowledge of the underlying cause. When a spreadsheet is cleaned-up because it had a reporting error, all parties involved move-on from the issue. Since the spreadsheet was never the root-cause of the original issue, the same reporting error is seen again in another report within a year. The NAO described this as a culture of tolerating workarounds. Each workaround carries a cost, and none of them appear in anyone's plan.
Furthermore, there is a lasting impact on how data initiatives are regarded. When proposing investments, business cases built on hard statistics consistently outperform those based purely on conjecture. Data refinement often ends up labeled as a cost to be minimised, rather than being recognised as the foundation that enables success elsewhere.
What our data maturity baseline assessment covers
We evaluate six core categories to determine data maturity and identify gaps for improvement.
Strategy
Has your leadership team defined their requirements for organisational information, aligning them directly to strategic goals? A strategy tucked away in an unread file yields little value. Without clear direction, enhancements merely address the most recent issue rather than the highest priority.
Governance
Which team maintains ownership for individual datasets, and who holds responsibility for approving modifications? A surprising number of technical complications stem directly from unsettled questions of functional ownership.
Assurance
Do staff members possess trust in available records? This requires evaluating consistency, accuracy, and overall data health across disparate platforms. Many public sector organisations suspect their information is faulty without grasping the true severity or precise locations.
Infrastructure
Understanding where information is stored, how it flows, where copies reside, and where it remains trapped inside legacy systems. While this proves the most costly area to remediate, mapping these flows presents the strongest justification for funding.
Insight
Are employees receiving timely analytical support, or does generating basic reports require manual labour? This is where the overall impact of your broader data ecosystem becomes apparent.
Culture
Frequently overlooked yet extremely challenging to evaluate. Do leaders feel confident making choices using current reports, or do they rely on unofficial workarounds? Do staff have sufficient training to resolve errors, or are problems left unaddressed?
Why operational team members should be involved in a data maturity assessment
Baseline data maturity assessments regularly reveal a disconnect between how senior management perceives operations and what happens on the ground. Executives review polished dashboards. Meanwhile, staff manage the underlying friction: manual data entry, external spreadsheets, and redundant verification routines created to bypass unreliable tools.
Comparing these perspectives side-by-side uncovers valuable insights. It exposes hidden operational bottlenecks alongside misplaced confidence in current systems.
The impact of data maturity baseline reporting
Debates steadily shift away from vague complaints regarding information quality and you gain the ability to highlight high-risk areas and direct funding where it yields maximum return.
It also delivers objective findings that finance departments or committees can endorse. The structured evidence carries far more weight during budget reviews than subjective opinions, ensuring trade-offs are evaluated openly.
Additionally, it creates a defensible starting point for tracking performance. Ongoing data improvements take time, particularly in complex environments like public services, so demonstrating tangible, incremental progress is essential for securing long-term funding.
Considerations for new data managers and leadership
If you are recently appointed to lead data functions, establishing a data maturity baseline proves invaluable. Your initial months offer a unique window to ask difficult questions, providing objective data that belongs to your strategy rather than inherited legacy issues.
Starting small without a major overhead
Our complimentary online Data Maturity Assessment takes under ten minutes to complete, highlighting organisational strengths alongside vulnerable areas. Whilst it is not exhaustive, it delivers actionable evidence to spark initial conversations.
A data maturity assessment is a structured review of how well an organisation manages and uses its data. It measures current capability across areas such as strategy, governance and culture, giving a clear baseline of strengths and weaknesses that can be used to prioritise improvements and support funding decisions.
Why do public sector organisations need a data maturity baseline?
A data maturity baseline turns known data problems into evidence that finance teams and boards can act on. Without it, concerns about data quality tend to sound like opinions, and funding often goes to the most senior or loudest voice rather than the area with the greatest need.
What does it cost to work without evidence of data maturity?
Working without evidence leads to poorly targeted budgets, repeated fixes and undervalued data work. Teams treat symptoms rather than root causes, so the same errors return, and manual workarounds build up as hidden costs. Data improvement is also more likely to be seen as a cost rather than an enabler.
Why should operational staff be involved in a data maturity assessment?
Operational staff should be involved because they see how data really works day to day. Senior leaders usually see finished dashboards, while frontline teams deal with manual re-keying, extra spreadsheets and repeated checks. Comparing both views exposes hidden problems and misplaced confidence that a leadership-only assessment would miss.
How does a data maturity baseline help secure funding?
A data maturity baseline gives decision makers structured, objective evidence instead of subjective opinion. It highlights the highest-risk areas so funding can go where it has the most impact, makes trade-offs visible, and creates a starting point for showing progress over time, which helps maintain long-term investment.
How long does the Butterfly Data Maturity Assessment take?
The Butterfly Data online Data Maturity Assessment takes under ten minutes and is free to complete. It gives a tailored view of your organisation's data strengths and weaker areas. It isn't a full audit, but it provides a practical starting point for conversations about data improvement.
We are delighted to welcome Ben Clare, Eleanor Dilks and Luke Rose to our Butterfly Data team, as our 2026 cohort of graduates.
Ben Clare is joining us after graduating with a First in Economics from the University of Liverpool, where he combined his studies with three years working as a chef. Ben developed a strong grounding in Python and SQL through practical work with financial data during his degree and he is now looking forward to applying that quantitative mindset to real client problems. Outside of work, Ben is into dance music, cooking and long walks with his dog (usually ending at the pub!).
Eleanor Dilks is bringing experience from her BSc (Hons) in Natural Sciences with an R&D industrial placement at Sherwin-Williams, which focused on new product development and statistical analysis for quality control. Eleanor is keen to build on her programming and professional communication skills as she moves into data science. In her free time, she enjoys running, baking and reminiscing about growing up on a farm.
Luke Rose is joining us following his PhD in computational chemistry, where he researched conduction mechanisms in solid-state battery electrolytes. This work involved training machine learning models and building pipelines to process and visualise complex datasets. Luke is excited by the varied workload a consultancy like Butterfly Data offers and wants to explore as many corners of the data world as possible (which is just what our graduate programme has been designed for). Away from his new desk, he plays the piano and enjoys board games. Luke is also ambidextrous, so if there is ever a two-handed data-wrangling job going, he is your man.
Following the success of our original cohort in 2025, all three graduates have joined our Graduate Programme, where they will work through structured training, shadow experienced colleagues and also take on real client projects as they find their footing across data analysis, engineering, science and management.
Welcome again to the team, Ben, Eleanor and Luke!
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