Senior leaders are familiar with the ritual: a Herculean cabinet-style submission, weeks of slide refinement, and then a Treasury approval event. Too often the event becomes an end in itself. The real judgement — whether the project will actually deliver its benefits to time, cost and quality — depends on a different set of documents, decisions and behaviours. This brief gives an SRO‑ready assurance pack mapped to the 2026 Green Book expectations and recent reforms to the centre’s assurance landscape, practical 90‑day priorities, and a short template you can use immediately to reduce approval-to-delivery rework. (See Treasury approvals guidance and Green Book 2026.) https://www.gov.uk/government/publications/treasury-approvals-process-for-projects-and-programmes/treasury-approvals-process-for-projects-and-programmes https://www.gov.uk/government/publications/the-green-book-appraisal-and-evaluation-in-central-government/the-green-book-2026
Why this matters now
Three policy shifts make a practical delivery assurance response urgent. First, Treasury’s clarified approvals process and the Integrated Assurance and Approvals Plan (IAAP) mean departments must show realistic, evidence‑backed assurance at each gateway rather than polished slideware. https://www.gov.uk/government/publications/treasury-approvals-process-for-projects-and-programmes/treasury-approvals-process-for-projects-and-programmes
Second, the Green Book 2026 places stronger emphasis on evaluation, counterfactuals and iterative appraisal — not just at business case but across the lifecycle — which forces changes in how Benefits Realisation and evaluation are evidenced to approvers. https://www.gov.uk/government/publications/the-green-book-appraisal-and-evaluation-in-central-government/the-green-book-2026
Third, the centre’s assurance body has been reformed to concentrate effort on the most strategic programmes and to expect clearer Delivery Confidence Assessments (DCAs) and demonstrable exit criteria from major programmes. This changes the incentives for both SROs and the centre. (See NISTA annual report and GMPP commentary.) https://www.gov.uk/government/publications/nista-major-projects-annual-report-2025-26/nista-major-projects-annual-report-2025-26
What senior leaders should demand from an SRO-ready assurance pack
An approval should be a controlled go‑ahead, not a permission to proceed into uncertainty. The assurance pack below is the minimum the board or Accounting Officer should expect before an approval event:
1) One‑page Delivery Confidence Summary: current DCA, top five risks with quantified impact, and required mitigations (owners and due dates). Use the DCA categories used in the GMPP so centre reviewers have a common frame. https://www.gov.uk/government/publications/nista-major-projects-annual-report-2025-26/nista-major-projects-annual-report-2025-26
2) Integrated Assurance & Approvals Plan (IAAP) extract: clear milestones for Gate 0–5, external assurance points, and the evaluation plan (who will measure benefits, when, and with what methods). Treasury now expects an IAAP that aligns with Green Book evaluation steps. https://www.gov.uk/government/publications/treasury-approvals-process-for-projects-and-programmes/treasury-approvals-process-for-projects-and-programmes https://www.gov.uk/government/publications/the-green-book-appraisal-and-evaluation-in-central-government/the-green-book-2026
3) Benefits Realisation Register (front‑loaded): a short register mapping each monetised and non‑monetised benefit to a metric, owner, baseline, current trend and evidence source — not high‑level aspirations but measurable targets to the SRO level.
4) Commercial & supplier assurance snapshot: single side showing supplier landscape, single‑point failure risk, key contract levers and exit options. The centre looks for early supply‑chain clarity, especially on critical path third parties.
5) Evidence bank pointers: where the reviewers can find the detailed documents (technical architecture, security sign‑off, user research, integration testing results) and the version/date stamp. Decision‑makers should not have to hunt for evidence during the event.
Three 90‑day priorities that reduce rework after approval
Priority 1 — Lock the first three delivery sprints and a proof‑of‑capability (not a wishlist): convert high‑risk assumptions into tested prototypes or contracts in the next 90 days. This significantly reduces schedule slippage and cost surprises during the first gateway.
Priority 2 — Assign an independent assurance lead and run fortnightly assurance health checks: an internal or third‑party assurance lead should run a light evidence review against the IAAP and the benefits register; escalate issues to the Programme Board within five working days.
Priority 3 — Formalise an exit / ‘leave‑the‑portfolio’ checklist: embed criteria (benefits matured, governance transferred, residual risk accepted) that must be met for the programme to step down from central oversight. The new central body will expect exit evidence; planning it before approval avoids later re‑work. https://www.gov.uk/government/publications/progress-report-on-the-government-major-projects-evaluation-review-action-plan/progress-report-on-the-government-major-projects-evaluation-review-action-plan-html
How to present this at the approval event (30-minute structure)
0–5 minutes: Executive one‑page Delivery Confidence Summary (DCA and top 5 risks). Decision-makers form an early impression from this page; let it set the frame.
5–15 minutes: Three things we will deliver in the next 90 days (linked to sprint outcomes and suppliers) and the evidence each will produce.
15–25 minutes: The three key mitigations for top risks (owner, cost, timeline impact) and what the Board must delegate now to prevent delays.
25–30 minutes: Clear ask and governance: specify the approval sought, any delegated authorities (change envelope), and the IAAP milestone that follows. Conclude with the benefits checkpoint and evaluation owner.
Practical templates and governance nudges
Use standardised templates for the Delivery Confidence Summary and Benefits Register so reviewers can compare projects quickly. The centre is increasingly intolerant of bespoke formats that hide risk.
Require each SRO to nominate an evaluation sponsor and a data steward before approval; the Green Book 2026 links appraisal to evaluation and will expect evidence of who measures outcomes and how. https://www.gov.uk/government/publications/the-green-book-appraisal-and-evaluation-in-central-government/the-green-book-2026
Insist on a commercial ‘pause & test’ clause in supplier plans for the first two milestones: that gives buying teams leverage if a supplier under‑performs and reduces the temptation to accept early optimistic performance statements without verification.
What success looks like at 6 and 12 months
At 6 months: First three sprints delivered to agreed scope or de‑scoped via a governance decision; benefits metrics show credible baselines and early trend data.
At 12 months: Evidence of benefits delivery for at least one major metric; a formal exit review or reclassification of central oversight if appropriate; and a documented lesson set captured for future approvals.
If these milestones are not met, the pack you presented at approval should contain the contemporaneous evidence explaining why — and who authorised the change. That discipline is the essence of accountable delivery assurance.
“An approval is a controlled go‑ahead, not an open cheque. If you can’t point to who will measure the promised outcome, when and how, you should not expect a durable delivery confidence rating.”
Antares recommended actions
These are Antares's recommended first actions for organisations turning the issues in this article into practical governance and delivery.
- Adopt the SRO‑ready assurance pack template (Delivery Confidence Summary, IAAP extract, Benefits Register, supplier snapshot, evidence bank) immediately for every programme moving to Treasury approvals.
- Schedule a 90‑day delivery milestone plan at the point of approval and make it the Board’s first checkpoint.
- Nominate an independent assurance lead and an evaluation sponsor before approval; record their names in the IAAP.
- Require a commercial ‘pause & test’ clause into early supplier milestones to preserve procurement leverage.
- Use standardised templates aligned to GMPP/NISTA DCA language to speed central review and reduce information requests.
- Publish a short 12‑month exit plan in the IAAP showing benefit measurement and transfer to BAU responsibilities.
- Embed the Green Book 2026 evaluation steps into the IAAP rather than treating evaluation as an afterthought.
- Run a post‑approval lessons short loop: capture three concrete lessons within 60 days and feed them into the next approval pack.
