BT Global — Design System
Building a single source of truth for one of the world's most recognised telecoms brands
Redesigning a critical financial system for tens of thousands of pension scheme members
The Problem
BT Global's digital products were growing faster than the systems governing them. Across multiple product teams, markets, and platforms, designers and developers were making independent decisions about patterns, components, and visual language — producing an estate that was inconsistent, increasingly difficult to maintain, and falling short of the accessibility standards expected of a global brand.
There was no single, authoritative design system in place. What existed was a patchwork of outdated guidelines, locally adapted components, and undocumented decisions that had accumulated over years. For a brand operating at BT's scale — across global markets, multiple languages, and a vast range of digital touchpoints — this wasn't just a design problem. It was a strategic liability.
My Role
I was brought in by TCS as an embedded Design Director within BT Global, working directly alongside BT's existing internal design and development teams. This was a deliberate integration rather than a typical agency engagement — I sat inside the organisation, understood its constraints and culture, and was accountable for the quality and direction of the system alongside the teams already in place.
My responsibilities covered creative direction, brand oversight, delivery management, and team leadership across the full lifecycle of the design system — from establishing foundations to adoption across product teams.
The Core Challenge
Building a design system for a single product team is hard enough. Building one for a global organisation with multiple existing teams, entrenched ways of working, and a brand as tightly governed as BT's is an order of magnitude more complex.
The technical challenge — creating a comprehensive, scalable component library with robust documentation — was substantial. But the organisational challenge was equally significant. Design systems only succeed if teams actually use them. That means the system has to be easy enough to adopt that it becomes the path of least resistance, and authoritative enough that teams trust it over their own locally evolved patterns. Getting both right simultaneously, across teams with different priorities and levels of design maturity, required as much change management as it did craft.
Key Decisions
Auditing before building. The instinct on a project of this kind is to start creating. We didn't. Before a single component was designed, we conducted a thorough audit of what existed across BT Global's digital estate — cataloguing patterns, identifying inconsistencies, and understanding which locally evolved solutions were actually worth preserving. This meant the system we built absorbed the best of what was already there rather than forcing teams to abandon work they trusted.
Accessibility as a foundation, not a retrofit. Rather than treating accessibility compliance as a checklist applied at the end, we embedded WCAG standards into every component specification from the outset. Every colour token, type scale, interactive state, and focus behaviour was designed with accessibility as a first principle. This was a non-negotiable given BT's public-facing obligations, but it also produced a more considered and robust system overall.
Documentation designed for adoption. A design system without clear documentation is just a Figma file nobody uses. We invested heavily in usage guidelines, best practice examples, and implementation support — written for both designers and developers, in language that made the right choice the obvious choice. The goal was a system that teams could onboard to independently, without needing a workshop or a call with the core team every time.
Outcome
The BT Global Design System was adopted across multiple product teams and became the single source of truth for digital design across the global estate. Design-to-development time reduced measurably as teams moved from bespoke, locally produced components to a shared, documented library. Accessibility compliance improved consistently across products, meeting the standards required for a brand operating at BT's scale and visibility.