Strangford Lough Crossing — Interactive Feasibility Dashboard

For the attention of: the Minister for Infrastructure, MPs, MLAs and councillors with a constituency interest in the Ards Peninsula, Lecale and Strangford Lough.

Sixty years after the 1961–64 Stormont bridge proposal, and thirteen years after the Department’s last internal review, the case for a fixed crossing at the Strangford Narrows has never been tested using current DfT TAG (Transport Analysis Guidance, formerly WebTAG) and HM Treasury Green Book methodology under the Better Business Case (5-Case Model) framework adopted across NI public-sector investment appraisal in 2021. The £500m figure cited in the Assembly originates in a 2024 internal correspondence note (FOI DFI-2024-0412), not a professional engineering assessment.

On 17 July 2026, Belfast Live reported that a DfI spokesperson confirmed the Minister had visited the area, met elected representatives on the case for a bridge crossing, and “is now giving consideration to this issue” — the first Departmental (not just Ministerial) acknowledgement of active engagement with the case. That consideration has not yet translated into a commissioned study, a Ministerial direction, or a timeline: a councillor’s April feasibility-study motion remains unanswered as of this report. This brief is the evidence base to close that gap.

The catchment that crossing would serve — Ards & North Down — is named by the Ulster University Economic Policy Centre as the lowest-performing of Northern Ireland’s eleven council districts by GVA per capita. The Council’s own 2025 Annual Performance Update Report places its GVA per head at £14,847, with the gap to the NI average holding between minus 42% and minus 44% for over seven years. Belfast generates more than three times the economic output per resident.

This dashboard puts the appraisal arithmetic in your hands. Every input is adjustable, every default is sourced in the Methods & sources tab, and the recommendation updates live. At the ministerial-anchored £500m capital cost with credible TAG-range inputs and HM Treasury’s own declining discount-rate schedule (Green Book Annex 6), the central case returns a BCR of 2.47, NPV +£1,048m, and an NI Executive net position of −£154m over 60 years, closeable to zero at approximately a £4.00 toll. Every major funder’s own attributable share clears the bar independently: NI 2.25, UK 1.80, Ireland 3.59. Four one-click presets show what combination of toll, paying share, rates uplift and funding mix brings the NI Executive to net break-even by year 10, 20, 40 or 60 respectively — borrowing against a reliable revenue stream to fund productive infrastructure, not a call on the block grant with no offsetting income. That distinction is topical: the new UK Prime Minister, Andy Burnham, took office on 20 July 2026 on an explicit pledge to finance investment without unsettling the bond markets that price UK borrowing. A revenue-backed crossing is a live example of the model that answers that test. The dashboard is equally honest about the scenarios in which the case does not stand — the low-demand stress preset returns BCR 0.85, and the Treasury 7% discount-rate sensitivity returns BCR 1.26, both below the 1.5 high-value-for-money threshold.

Strangford Lough’s statutory designations — Special Area of Conservation, Special Protection Area, Area of Special Scientific Interest, Ramsar wetland of international importance, and Northern Ireland’s first Marine Nature Reserve — impose a high bar but not an infinite one. The same designations were not deemed to make the Narrow Water Bridge unbuildable.

The Carlingford Lough Ferry, operating between Greenore and Greencastle some thirty miles south on the same coast, provides a live demonstration of why the status quo is not a safe default. Its 2025 season ended in September; as of May 2026 it has been confirmed as not operating on any date this year, with no return date given. The Shared Island Fund has already responded to that fragility at Carlingford with the Narrow Water Bridge, due to open in 2028. Strangford has no equivalent answer.

The campaign is not asking for a bridge. It is asking for a time-limited, independent feasibility and options appraisal — nothing more.

Open the dashboard · Kevin Barry BSc(Hons) MRICS, Quintin QS