The comparison
What else this money buys
£108m has been committed over a decade to the twelve-route programme. It will not buy everything the 2016 review planned, and finishing the full network will probably need more. Set against what the same county spends on its roads, even that is small. And the growth Greater Cambridge is planning is meant to help pay for it.
One junction, four times the cycling programme
National Highways' own senior project manager for the A428 Black Cat to Caxton Gibbet scheme, Paul Salmon, told the BBC in November 2025 that building "such a complex three tier junction" at the Black Cat roundabout "is why it costs half of the scheme cost" — the "most significant and complex part of the project."
Half of a confirmed £1bn road scheme — roughly £500 million — is being spent rebuilding a single roundabout.
Source: BBC News, 17 November 2025, "Half of £1bn work is on Black Cat roundabout alone", quoting National Highways senior project manager Paul Salmon. The scheme in full — ten miles of new dual carriageway and two rebuilt junctions between the Black Cat and Caxton Gibbet roundabouts — costs £1 billion.By the standard this county spends on its roads, half of one junction would pay for everything committed to the Greenways more than four times over — and for the full 2016 network even if finishing it costs twice what is committed.
The wider comparison
None of this is an argument against building roads. It is an argument against the idea that the Greenways are expensive: £108m, or even double that to finish the full network, is small next to what this county spends on its roads.
| Scheme | Length | Cost | Roughly per mile |
|---|---|---|---|
| Greater Cambridge Greenways — committed so far (twelve routes) | ≈93 miles (150km) of new and upgraded route | £108m committed | ≈£1.2m |
| A428 Black Cat to Caxton Gibbet — the Black Cat junction alone | one roundabout | ≈£500m | — |
| A428 Black Cat to Caxton Gibbet — full scheme | 10 miles | £1 billion | ≈£100m |
| A14 Cambridge to Huntingdon | 21 miles | £1.5 billion | ≈£71m |
| Ely southern bypass (a county-scale scheme, not National Highways) | just over 2 miles | £49m | ≈£23m |
The 150km is GCP's own description of the network (Joint Assembly, February 2025). The committed £108m will not deliver everything the 2016 review planned; even if finishing the full network cost twice as much, it would come to about £2.3m a mile — a small fraction of any road scheme in the table.
The Ely bypass alone — a single county road scheme just over two miles long — cost nearly half of everything committed to twelve cycling routes across the whole sub-region.
By the standard this county spends on its roads, the Greenways are a rounding error — even if finishing the full network costs twice what is committed.
Sources: gov.uk — half-a-billion pound contract award · gov.uk — works to start on £1bn transformation · A14 end-of-scheme brochure (PDF) · Construction Index — Ely bypass cost escalation · the Greenways budget breakdown →Paying more, getting less
The £108m has not bought what was planned. In 2020 the Executive Board approved eleven of the twelve routes with outline budgets totalling £76m. By 2026 the agreed budgets for the same eleven routes added up to £98.5m — about 30% more. Over the same years almost every bridge and underpass came out of the programme or was downgraded, along with many of the village links.
| Greenway | Approved 2020 | Agreed budget 2026 | Change | Lost or downgraded from the 2016 plan |
|---|---|---|---|---|
| Waterbeach | £8.0m | £11.0m | +38% | Railway alignment; the Cam bridge at Baits Bite Lock |
| Fulbourn | £6.0m | £7.1m | +18% | Longer-term rail-corridor paths to the Chisholm Trail and Science Park |
| Melbourn | £6.5m | £15.3m | +135% | The A505 bridge into Royston and the path to it |
| Comberton | £9.0m | £8.6m | −4% | Long Road underpass, now a surface crossing |
| St Ives | £7.5m | £6.7m | −11% | Flood-relief paths, Holywell bridges, Fenstanton link; Over spur suspended |
| Barton | £10.0m | £11.9m | +19% | Westward links to the Eversdens and Comberton Village College |
| Sawston | £9.0m | £6.7m | −25% | The disused-railway route, paused on cost |
| Bottisham | £5.0m | £10.3m | +107% | Wilbraham Road link (Riverside added); a later Ditton Lane underpass proposal rejected |
| Swaffhams | £4.5m | £6.4m | +43% | Swaffham Prior; the off-road route through Swaffham Bulbeck |
| Horningsea | £2.5m | £2.8m | +14% | Cam bridge and Lode link (never included) |
| Haslingfield | £8.0m | £11.6m | +46% | Hauxton route and its Cam bridge (realigned via Grantchester) |
| Eleven routes | £76.0m | £98.5m | +30% | Bridges or underpasses proposed at twelve places; none built |
The 2020 figures are the outline budgets approved before detailed design; Linton was approved separately in 2017 and is not included. Some increases reflect scope that was added — Bottisham took on the shared Cambridge-end section and the Riverside works — and construction prices rose from the start of 2021 to a peak in late 2024. Where budgets fell, as on Sawston and St Ives, it is because scope was removed, not because anything got cheaper. Sources: February 2020 · June 2020 · October 2020 · December 2020 approvals · GCP draft budget 2026/27.
What a decade of delay cost
Nobody can say exactly how much more of the 2016 network £108m would have built if construction had begun in 2017. The direction is not in doubt.
Prices. Work bought before 2021 was bought before the rise in construction prices that the Office for National Statistics records from the start of 2021 to a peak in late 2024. The routes still being consulted on or redesigned through those years paid the higher prices.
Process. Most corridors were consulted two or three times. Waterbeach, Haslingfield, Swaffham and Fulbourn's phase 3 were each realigned after design work had been done, and the Grantchester route spent fifteen months in the High Court. All of that was paid for; none of it is on the ground.
Comparisons. Ireland's Waterford Greenway — 46km along a disused railway, agreed with around 120 landowners — cost €15m and opened in 2017. County Mayo's Great Western Greenway, 42km, cost €5.7m and was built in about two years. The South Kerry Greenway, held up for years by objections and legal challenge, saw its estimate rise from €16.1m in 2015 to more than €20m by 2020, before construction had started. Rural rail-trails cost less per kilometre than the mix of urban and village work in Greater Cambridge, so these are not like-for-like costs; the lesson is about time. Sources: Irish Times, June 2020 · Enable Research, March 2026.
Finishing the whole 2016 network will now very probably need more than is committed. Had the programme started building in 2017, it would have needed far less.
The Greater Cambridge Partnership has been well funded throughout — a City Deal worth up to £1bn — and the greenways are one of its smaller lines. The problem has been value for money, not money: more spent, for less network, more slowly.Growth can help pay for it
Greater Cambridge is planning for about 50,000 more homes and 73,000 more jobs by 2045, in the draft Local Plan. The people who live and work there will need safe routes into Cambridge and between villages, and the planning system already expects growth to help pay for the transport it needs.
It does so in two ways. Section 106 agreements, negotiated site by site, pay for what a development needs, and can build a route outright: Waterbeach New Town's A10 bridge and Mere Way upgrade were a planning obligation. A Community Infrastructure Levy — a fixed charge per square metre of new floorspace, pooled for wider infrastructure — is being introduced alongside it. Draft rates are £60 for homes and £175 for offices and labs; the schedule was examined in October 2026.
Growth was always meant to pay its share. Under the 2014 City Deal, local partners undertook to raise a further £500m, with developer contributions among the sources, and the Greater Cambridge Partnership's current budget assumes about £230m of future section 106 income.
The greenways are exactly the kind of infrastructure developer contributions exist to fund. The levy's spending plans do not yet name them.
The councils propose the levy for "strategic transport infrastructure"; their infrastructure statement names neither greenways nor cycling. The County Council asked that levy-funded transport "prioritise safe, direct, and inclusive walking, wheeling, and cycling routes from the start". Sources: Cambridge City Council cabinet report on the levy · levy supporting statement · Cambridgeshire County Council's response, March 2026 · City Deal document.None of this should be overstated. The levy is expected to raise £5–10m a year, against a strategic transport funding gap the councils put at £272m (the County Council's figure is about £222.5m). The County Council has also warned that section 106 contributions since 2022 have run well below what the budget assumes. Developer money will not finish the network on its own, which is why it has to buy more network, faster, than the last decade's money did.