Update: 22-05-2026 – Anyone who says “the Strangford ferry meets the need, why build a bridge” can now be answered with: “The Carlingford ferry met that need too, until it didn’t. The market removed it in May 2026, as confirmed today, with no advance notice and no replacement. A peninsula community cannot stake its connectivity on a service that depends on insurance premiums, fuel costs and a single operator’s commercial calculation. A public service also cannot continually ignore the obvious and maintain a loss making service over Strangford Lough. Is a replacement ferry on the cards, given the breakdowns and long service history of both vessels ? A fixed crossing is the only piece of infrastructure that delivers permanent connectivity. The Carlingford community is learning that lesson right now. Strangford should not have to learn it the same way.”

Strangford Lough Crossing — Interactive Feasibility Dashboard

Strangford Lough Crossing – Heatmap

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, a fixed crossing at the Strangford Narrows has never been tested using current DfT TAG (Transport Analysis Guidance, formerly WebTAG) methodology or the Treasury Green Book methodology under the Better Business Case (5-Case Model) framework adopted across UK investment appraisal in 2021. The £500m figure cited in the Assembly originates in a 2024 internal briefing note (DfI FOI ref. DFI-2024-0412), described in that document as a “very rough cost estimate” — not a professional engineering assessment.

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 mid-position and bottom for 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, and the recommendation updates live on each tab. At the ministerial-anchored £500m capital cost (adjusted to £625m applying the standard HM Treasury optimism bias of 1.25×) with credible central-case demand, the central case returns a BCR of 2.41, NPV +£994m, and an NI Executive net position of −£162m over 60 years, closeable to zero at a £3.75 toll. The dashboard is equally honest about the scenarios in which the case fails: the low-demand stress test at 1,200 vpd returns BCR 0.83.

Strangford Lough’s statutory designations — Special Area of Conservation, Special Protection Area, Ramsar wetland of international importance, and Northern Ireland’s first Marine Nature Reserve — impose constraints on any crossing, but they do not make one unbuildable. The same designations were not deemed to make the Narrow Water Bridge unbuildable.

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

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SLC Heatmap

We have published an interactive traffic heatmap for the proposed Strangford Lough Crossing. It is a visual tool built directly on Department for Infrastructure count-point data (DfI Traffic Census 2023, OpenDataNI) and the TAG-compliant feasibility appraisal published in March 2026. It is not opinion. It is the evidence — geocoded, colour-coded and interactive. Move the slider, switch between BEFORE and AFTER, and see how a 1,111m fixed link redraws the traffic map of South-East Down and the Ards Peninsula.

The Before Picture

Switch the heatmap to BEFORE Bridge and the problem is immediate. The A21 Newtownards corridor carries 21,200 vpd (CP507, DfI Census 2023) — deep red, saturated, the only meaningful artery in or out of the peninsula. Michelle McIlveen MLA has noted it as the most overloaded corridor in the area. The A1 Loughbrickland–Newry carries 29,260 vpd — the highest count in the Down area. The A22 round-lough route carries 9,100 vpd (CP512) as the long-way-round alternative. The Ards Peninsula is, in network terms, a dead-end for through traffic.

The Strangford ferry carries just 650 vpd (DfI FOI DFI-2024-0412) — 83% of drivers avoid it because of cost, wait times and unreliability. And the A25 Downpatrick–Castlewellan–Newry route is barely visible on the map: a chronically underfunded corridor that should be a strategic east–west link but is not treated as one.

Two Break-Even Thresholds — and Why Both Are Honest

The appraisal can be tested two ways:

• TEE-only break-even: 285 vpd. Counting transport user benefits alone (journey time saving, vehicle operating costs, reliability) against £625m adjusted capex. Today’s ferry already carries 650 vpd — more than twice this threshold. Already cheaper than the 60-year ferry liability of £110m (PV).
• Full Green Book break-even: ~5,000 vpd. Adding societal benefits — health, tourism, labour-market access, carbon — under the HM Treasury Better Business Case standard. The dashboard’s Yr 5 central forecast of 14,100 vpd is comfortably above this.

What the Slider Shows

Switch to AFTER Bridge and move the slider from 0 vpd upward:

• 285 vpd — TEE-only break-even. Transport user benefits alone cover £625m adjusted capex. Ferry today: 650 vpd — already above this.
• 1,200 vpd — low-demand stress test. BCR 0.83. Case honestly fails the comprehensive test at this level. Included to show the full envelope.
• 5,000 vpd — full Green Book break-even. Comprehensive BCR = 1.0. Both tests now pass.
• 14,100 vpd — central Yr 5 (dashboard). BCR 2.41, NPV +£994m, NI Executive net position −£162m (closeable to zero at £3.75 toll). Cumulative benefits cover adjusted capex by operating year 12.
• 16,000 vpd — high case (Corran Narrows reference class). BCR ~3.0, NPV +£1.4bn.

The design capacity of the structure is 8,000–12,000 vpd. The bridge is never the constraint — the surrounding network is.

New Corridors Unlocked

The heatmap shows what the bridge makes possible — not just more traffic on existing roads, but new destinations becoming reachable:

• Portaferry → bridge → Strangford → Downpatrick → A1 → Newry/Dublin. Currently impossible without a 75km detour.
• The Lecale coast warms: Ardglass, Killough, Bishopscourt Circuit, and the Ballykinlar GAA Centre of Excellence become viable destinations as the Ards Peninsula opens up as a catchment. The B1 Killough Road from Downpatrick and the A24 from Clough warm throughout.
• The fishing industry connects. Portavogie (NI’s largest whitefish harbour), Ardglass and Kilkeel (Ireland’s largest fishing port by tonnage) gain a direct inter-harbour corridor — currently requiring a 60km+ detour via Newtownards.
• The A25 activates. Downpatrick–Castlewellan–Newry begins to carry the traffic it was built for — and exposes the upgrade case for this historically neglected route.
• The A22 round-lough route cools by −18%. The A7 Downpatrick–Crossgar–Saintfield–Comber–Newtownards corridor cools too — congestion relief, not just new demand.
• The A21 Newtownards corridor cools by −15% at central demand — measurable relief for the most overloaded road in the area.
• Cross-border Newry–Dundalk warms at high vpd. Island connectivity, finally.

Economic Activation of Ards and North Down

The bridge does not just move people. It repositions the Ards Peninsula as a location for business. Lower premises costs, fixed-link connectivity, and access to both Belfast and the south of the island make the borough viable for occupiers who currently discount it.

The heatmap shows two-way warming throughout the borough — inbound workers, outbound goods, new residents. DfI economists will scrutinise every figure, and they should. Heat intensity between DfI count points is proportionally interpolated — clearly labelled as such. Every measured figure comes from DfI’s own census.

The Break-Even Tab

A dedicated tab explains both break-even thresholds side by side — TEE-only (285 vpd) and full Green Book (~5,000 vpd) — with the derivation of each set out in plain language and a link to the full feasibility dashboard methods.

The Bridge Editor

A separate tab lets you position the bridge alignment yourself. Move the four handles — E portal, W portal, Portaferry roundabout, Strangford roundabout — and watch the span update in real time. The NI Roads (Mr Roads) reference alignment of 1,111m is shown.

Explore the Heatmap

The interactive heatmap is live now. Please share it, embed it on your own sites, and send feedback. The full TAG appraisal and feasibility dashboard are available at slc-feasibility-dashboard.netlify.app. DfI is the decision-maker. The data is on the table — and it is there for them to scrutinise.

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Data Sources

• DfI Traffic Census 2023 (OpenDataNI, published November 2024): CP507 A21 Newtownards 21,200 vpd · CP419 A1 Loughbrickland–Newry 29,260 vpd · CP513 A7 Downpatrick 12,670 vpd · CP512 A22 Comber 9,100 vpd · CP444 A20 Kircubbin 7,280 vpd.
• Strangford ferry: 650 vpd (DfI FOI DFI-2024-0412) · £3.52M/yr operating cost · £1.0M/yr net subsidy (operator-stated) · 60-year PV liability £110M · avoidance rate 83%.
• Break-even derivation: TEE-only 285 vpd = £625m PVC ÷ (£8/trip TAG benefit × 24.9 PV factor); full Green Book ~5,000 vpd = feasibility dashboard full appraisal engine including societal impacts and carbon (DESNZ Dec 2024).
• Capex anchor: £500m stated by Minister Kimmins, Assembly 11 May 2026 · adjusted to £625m at 1.25× HM Treasury optimism bias · source described as “very rough cost estimate” in DFI-2024-0412.
• Appraisal: Quintin QS TAG-consistent appraisal, May 2026 — Kevin Barry BSc(Hons) MRICS · consistent with DfT TAG / HM Treasury Green Book 2025 / 5-Case Model.
• Demand reference class: HITRANS Corran Narrows Fixed Link Feasibility Study (2023, Stantec UK / COWI).
• Heat intensity between DfI count points is proportionally interpolated. Projected new corridor figures (Lecale, Ardglass, Kilkeel, Ballykinlar, Bishopscourt) are Quintin QS suppressed demand model estimates — not DfI census data.