The legacy migration tipping point: Why AI changes everything

If you’re a senior tech leader, legacy systems are likely a permanent fixture on your ‘to do’ list. These systems can be costly to maintain and difficult to adapt, making it a challenge to keep pace with the evolving needs of modern public services.

Historically, legacy systems have stuck around because the risk of change feels higher than the cost of staying put. Monolithic architectures and complex, undocumented dependencies can make migration feel less like a standard engineering project and more like trying to perform surgery on a moving patient.

But the landscape is shifting. We’re seeing real progress in digital transformation, as strategic ambition meets delivery - and AI is the catalyst making change possible.

AI is turning the tide

Today, AI-assisted approaches are making a real difference across the migration lifecycle. In our work with government clients, we’re seeing three exciting shifts:

• Rapid code comprehension: AI tools can analyse decades of legacy code in a fraction of the time it takes for manual review, surfacing hidden risks and dependencies instantly.
• Intelligent refactoring: Automated tools make it easier to translate or rewrite legacy components into modern languages.
• Confidence at speed: AI-assisted testing means teams can move faster and deploy more frequently without compromising security or stability.

Together, these shifts are changing the fundamental economics of migration. If you’ve been waiting for the "right time" to tackle legacy debt, the odds might now be firmly in your favour.

Powering the progress beyond AI

While AI is a powerful engine, it needs a well-built vehicle to deliver real value. We see three strategic pillars being adopted in organisations that succeed with AI:

• API-first architecture: By "wrapping" legacy systems in APIs, you decouple new services from old dependencies. This means you can deliver modern user experiences immediately, without waiting for the full migration.

• Platform thinking: Building shared internal platforms, like automated deployment pipelines and self-service infrastructure, means every successive migration becomes faster and cheaper.

• Modern engineering practices: Strong foundations like continuous integration (CI) and automated testing aren't just "nice-to-haves." They’re the guardrails that make AI-assisted delivery trustworthy and repeatable.

AI isn’t a magic wand. If you apply AI to fragmented or "siloed" data, you’ll get poor results. Investing in data foundations like quality, accessibility and usability is what actually unlocks AI’s potential.

What good looks like in practice

The good news is that scalable, repeatable migration isn’t just a theory; it’s happening now. Our work with organisations such as HMRC and Defra shows what’s possible when you combine AI with engineering excellence. Instead of high-risk, big bang transformation, we have pursued steady, incremental progress. Here’s what we’ve learned works:

• Incremental strategies: Manage risk by learning as you go.
• Team autonomy: Using self-service models so teams can move at pace.
• Responsible AI: Treating AI as a high-powered tool, not a substitute for strategy.
• Repeatable patterns: Stop reinventing the wheel and start reusing what works across departments.

Three questions to ask today about your legacy strategy

If you’re ready to transform the legacy challenge into digital advantage, here are three questions to bring to your leadership meeting:

• Where can we reduce risk today? Which systems carry the most service risk, and how can we use incremental steps to make progress safer?
• Where can AI provide a "quick win"? Which parts of the backlog are ready for AI-assisted refactoring today?
• Are our foundations ready? Do we have the data quality and engineering standards in place to support a faster pace of change?

Join us to learn how your organisation can accelerate legacy migration

We understand these aren't easy questions to answer in a vacuum. That’s why Equal Experts is hosting a roundtable for senior IT leaders across government at Government Transformation Summit on 25 June.

This isn't a sales pitch or a broadcast; it’s an honest, peer-to-peer exchange of practical experiences. We’ll discuss what it actually takes to move from pilot projects to large-scale, reliable delivery. We’d love to have your voice in the room.