CPD — Continued Prolonged Delays

Methodology & Sources

CPD Index (0–100): CPD-C (Cost Performance) measures the proportion of schemes delivered at or near announced cost, with a severity penalty for overruns greater than 25%. CPD-D (Delivery Performance) measures the proportion of schemes free from significant delay, with a minor penalty for smaller slippages. The combined CPD score applies a 60/40 weighting — 60% CPD-D (Delivery) and 40% CPD-C (Cost), reflecting the judgement that delivery failure imposes compounding societal and economic costs beyond the overrun figure alone. A score of 100 indicates a perfect delivery record; 0 indicates complete systemic failure.

Clock: The live clock is computed from the scheme table on this page rather than from a stored total. It starts from the accumulated cost overrun on every scheme still live — any status other than Completed, Cancelled or Paused, with announced cost treated as zero where no published baseline exists — and then accrues construction inflation of 3.8% per annum (blended BCIS) on the live estimated portfolio from base epoch 30 April 2026. Completed, paused and cancelled schemes are excluded from the accrual. Both inputs are reproducible from the scheme table below, and the reconciliation panel shows the totals they derive from. Re-based 22 September 2026: the clock previously ran from a hand-selected subset of schemes that no longer reconciled with the published portfolio totals on this page.

Cost data: Announced costs are taken from original TfL Business Plans, GLA Budget papers, DfT/HS2 Ltd announcements and parliamentary statements. Current estimated costs are drawn from TfL Annual Reports, NAO reports, London Assembly Transport Committee papers, GLA Budget scrutiny documents, Mayor of London press releases, BBC London, and the Evening Standard.

Delay data: Weeks of delay calculated from original target completion date versus revised target or current date where no revised target exists. Where no completion date was formally set, delay is shown as — (not quantifiable).

2032 projection: The 2032 view uplifts each live scheme’s current estimated cost by compound construction inflation of 3.8% per annum over the six years from 2026, and leaves completed schemes at their outturn cost. It is computed from the scheme table, so it moves with the data rather than from a stored figure.

Primary sources: TfL Annual Reports & Business Plans · GLA Budget & London Assembly · National Audit Office · BBC London · GLA Capital Funding & Delivery Report Dec 2025 · NAO HS2 Update July 2024

ETI — recognised by infrastructure funders and development economists: The ETI framework mirrors the approach used by infrastructure funders, bond markets, and recognised development economists when assessing the productive value of public capital expenditure. Its components draw on HM Treasury Green Book benefit-cost ratio methodology, deprivation weighting consistent with Levelling Up Fund criteria, and network effect analysis aligned with WebTAG multi-modal appraisal guidance — the same analytical frameworks referenced by the Infrastructure and Projects Authority, development finance institutions, and institutional investors when evaluating public infrastructure programmes.

Disclaimer: This tracker is an independent professional accountability tool prepared by QUINTIN QS. It does not replicate, replace, or compete with any official government appraisal process. ETI scores and Stranded Value figures are derived from publicly available benchmark data and established appraisal frameworks — they are not the output of scheme-specific transport models such as TUBA or WebTAG-compliant multi-modal assessments. BCR inputs are drawn from published or analogous benchmarks, not bespoke modelling. Deprivation weighting is adapted from Levelling Up Fund criteria and is indicative in jurisdictions that use different deprivation indices. Delivery certainty scores reflect professional judgement applied consistently across all schemes. The methodology is fully disclosed, reproducible, and grounded in HM Treasury Green Book principles as updated in 2026 — but it carries the status of an independent analytical indicator, not a statutory appraisal. All figures are drawn from publicly available sources and are correct as of the date shown. If any government department holds more accurate data for a specific scheme, QUINTIN QS will update immediately upon notification. 🍓 If you believe any figure or fact shown here is incorrect, please write to mail@kevinbarryqs.com with the relevant scheme name, the correct figure, and a source reference — we will review and correct immediately if the evidence supports it. We are, after all, still human.

CPD Index — cost cap: The cost overrun % contribution to CPD-C is capped at 50 points — schemes with overruns above 100% score the maximum on this component. This prevents extreme outliers (e.g. schemes with 200%+ overruns) from distorting the index beyond its intended range.

CPD — about this acronym: CPD stands for Continued Prolonged Delays — a deliberate reference to Northern Ireland's Central Procurement Directorate, rebranded as Construction, Procurement, Delivery — the NI Executive body whose mandate is to ensure public infrastructure is built on time and on budget. The name is intentional.