Legacy Billing Transformation

Gardius directed a £125m programme for Enterprise, that provides connectivity backbone for nearly half a million British businesses, including a majority of the FTSE 100, by modernising billing platform. The successful delivery of this legacy transformation, significantly improving both operational efficiency and client satisfaction.

Client Profile: The UK enterprise division of a global telecommunications leader.

The Challenge: To execute a critical legacy transformation by replacing an end-of-life billing system with a modern, scalable platform, thereby mitigating significant business risk and enhancing future capabilities.

Our Solution: Gardius led the £125m programme from end-to-end, managing the complex technical migration, ensuring stakeholder alignment, and deploying a structured, risk-averse rollout strategy.

The Impact: Successfully decommissioned the high-risk legacy platform and delivered a modern, stable billing system, creating a future-proof foundation for new product innovation and improved operational agility.

The Situation 

The UK enterprise division of a global telecommunications leader was reliant on a core billing system that was approaching its end-of-life. This presented a significant, strategic business risk. The legacy platform's limitations were not just operational; they actively hindered the company's ability to innovate and launch new, more complex enterprise products. The core challenge was to execute a seamless transition to a modern platform, future-proofing a critical business function without disrupting the flow of revenue or customer data.

 Our Approach & Solution

Gardius was appointed to lead the £125m legacy transformation programme. Our primary objective was to deliver the new platform with certainty and control, mitigating the inherent risks of such a foundational change.

• Formal Programme Governance: To provide the necessary oversight for this business-critical initiative, we established a formal governance model aligned with the SAFe (Scaled Agile Framework). This ensured that all streams of work—from technical development to business readiness—were perfectly aligned through programme iand that senior stakeholders had full visibility of progress and risks.

• Structured, Phased Deployment: A key strategic decision was to structure the project as a phased deployment. The rationale was to systematically de-risk the migration. This allowed us to build, test, and prove the new platform in a controlled manner before the final, irreversible step of decommissioning the legacy system, guaranteeing business continuity.

• Proactive Stakeholder Management: We understood that the new system would impact multiple departments. We designed and executed a proactive communications and stakeholder engagement plan to ensure all business and technical teams were fully informed and prepared for the transition, which was critical for a smooth cutover and successful adoption.

The Results & Impact

The programme successfully retired the high-risk legacy system and delivered a modern, robust billing platform for the client. This was a true legacy transformation, focused on long-term capability rather than short-term fixes.

• Mitigation of Business Risk: The primary success was the elimination of the significant operational and security risks associated with the end-of-life platform.

• Enabled Future Innovation: The new, agile platform provided the technical foundation needed to support next-generation enterprise products and services, unlocking new revenue opportunities.

• Improved Operational Stability: The modern system enhanced the stability and reliability of the entire billing function.

• Lower Total Cost of Ownership: The new platform was more efficient to maintain and operate, reducing the long-term total cost of ownership compared to the outgoing legacy system.