Most public sector digital transformations don't fail at launch - they fail quietly afterwards. The software goes live, the project team stands down, and then, almost imperceptibly, the manual workarounds creep back in. The ROI evaporates. The audit arrives. This is the Modernisation Gap: the dangerous distance between technical delivery and organisational readiness. Bridging it requires something far more demanding than good project management - it requires Transformation Integrity, fiduciary stewardship, and a governance model built not just for Go-Live, but for the year that follows it. If you hold accountability for a public sector modernisation programme, what follows is worth your time.