The 251 UK civil-engineering and utility-network companies that publish a full profit-and-loss book £18.7bn of combined turnover building and maintaining Britain’s roads, power grid and telecoms networks — and, unusually for a trade that shares its DNA with building, most of them make respectable money. Kier Transportation, Kier’s highways arm, kept £35.8M on £622M — nearly 6p in the pound. F M Conway kept 5.4%, Ringway 5.6%, and M Group’s utility-network business a headline 9.3% — nearer 5.6% once a £22.1M one-off provision release is stripped out, which still puts it level with the roads firms. On the building sites next door, Wates Construction, the Wates group’s main contracting arm, turned £2.24bn into £1.3M (about £24M before a one-off pension charge — still barely 1%) and Morgan Sindall’s construction arm’s 4.1% counts as the national benchmark. Same diggers, same trade bodies, same insolvency risk — but the civils contractor working repeat frameworks for the state and the regulated utilities keeps roughly twice what a builder of someone else’s tower does. Figures are approximate — verify against a company’s own accounts before relying on any single number.
Why the same trade pays differently here
The client is the difference. A building contractor wins a one-off, fixed-price job from a developer and carries every risk to a thin sliver. A civils contractor mostly serves programmes: National Highways and local-authority highways frameworks, the electricity network operators’ grid build-out, water companies’ asset plans, national fibre rollouts. Frameworks run for years, work recurs (roads need resurfacing forever), prices carry indexation and target-cost mechanisms, and the client is a monopoly spender that needs its contractors solvent. That structure shows up directly in the accounts: the giants here cluster at 4–6% margins where building’s giants cluster at 0–4%.
Three caveats change how you read everything below. First, this is still contracting — the trade that produced Carillion’s collapse and took the water-and-civils contractor NMCN down in 2021. A blown-up firm exits the numbers entirely, so the map only ever shows survivors, and one bad target-cost job can still erase years of margin. Second, group stacking: Costain Group, the listed infrastructure group, and Costain Limited, its trading arm, both publish accounts at just over £1bn each — the same business twice; we keep the group and drop the arm. Third, and biggest: the energy transition has swept non-contractors into the map. The utility-networks side of this market now includes wind-turbine and battery makers’ UK arms, wind-farm owners, road concessions and cost-plus mega-project joint ventures — none of which earn a contractor’s margin, because none of them are really contractors. They’re labelled below and kept out of every competitive read. The wiring trades that connect these networks to buildings have their own map.
The giants
| Company | What it is | Turnover | PBT | TO YoY | Staff YoY |
|---|---|---|---|---|---|
| Siemens Gamesa Renewable Energy | wind-turbine maker’s UK arm — not a contractor | £1.64bn | £26.4M | +25% | +5% |
| BAM Nuttall | civils contractor (Dutch BAM group) | £1.48bn | £57.8M | +8% | +3% |
| Costain Group | listed infrastructure group | £1.05bn | £48.2M | −16% | −4% |
| Kier Transportation | Kier’s highways arm | £622.5M | £35.8M | +9% | +1% |
| F M Conway | roads contractor (family-founded; Vinci since Jan 2025) | £608.3M | £33.0M | +5% | +3% |
| Bylor Services | nuclear mega-project JV — cost-plus | £587.2M | £459k | +6% | −1% |
| M Group Water (Network Infrastructure) | utility-networks contractor (M Group) | £564.7M | £52.4M | +8% | +5% |
| Amentum Clean Energy | US group’s UK nuclear/clean-energy arm | £554.4M | −£148k | +83% | +78% |
| Ringway Infrastructure Services | highways maintenance contractor | £503.0M | £28.4M | +9% | −1% |
| Ferrovial Construction (UK) | Spanish group’s UK mega-project arm | £498.4M | £25.1M | +2% | +3% |
| R.J. McLeod (Contractors) | Scottish civils contractor (OCU Group, PE-backed) — 18-month period | £303.3M | £56.4M | — | — |
(Costain Limited, the group’s trading arm, also publishes at £1.01bn and is dropped as a duplicate.)
Read the genuine contractors first. BAM Nuttall at 3.9% on £1.48bn — down from an unusually strong 6.7% in 2024 — is the normal shape of heavy civils at national scale, and it’s growing revenue and headcount together. Kier Transportation (5.8%), F M Conway (5.4%) and Ringway (5.6%) are the highways-framework annuity in three flavours: resurfacing, maintenance and management of the road network, paid for by the state, year after year. M Group’s network-infrastructure business prints a headline 9.3%, but that’s flattered by a £22.1M one-off release of a remedial-work provision — the same provision that crushed the prior year to 1.8%. Underlying, it earns about 5.6%: utility-network work clusters with the highways band, and the whipsaw from 1.8% to 9.3% in two years is itself the lesson in how fast one job can move a contractor’s margin. Costain is the deliberate contrast — revenue down 16%, headcount down 4%, but £48.2M kept at 4.6%: a contractor shrinking on purpose, choosing margin over volume. And R.J. McLeod, the Scottish firm that does the earthworks under much of the country’s onshore wind — family-owned until its June 2024 sale to Triton-backed OCU Group — printed an extraordinary £56.4M on £303M — 18.6%. One caveat and one confirmation: those figures cover an 18-month period (the year-end was extended to align with OCU’s), so annualised it’s roughly £202M and £37.6M and would rank below Ferrovial, not above it; the margin, though, is period-neutral, and the prior twelve months ran at 16.1% — for this firm it’s structural.
Now the rows that aren’t contractors. Siemens Gamesa, the biggest company on the map, is a turbine maker’s sales-and-service arm — its 1.6% is manufacturing economics, not contracting. Bylor is the employment vehicle for the Bylor JV delivering the civil works at Hinkley Point C — it pays the 5,518-strong workforce and recharges the labour to the JV at cost: £587M of turnover, £459k of profit — a cost-plus vehicle whose margin sits with its parent groups by design, which is why it must never appear in a margin comparison. Amentum Clean Energy’s +83% turnover with +78% staff is a group business-transfer landing in the accounts, at breakeven. And Ferrovial’s UK arm runs £498M through just 582 employees — mega-project delivery where nearly all the physical work is subcontracted, so its 5.0% is a management-layer margin.
The shape of the market
Scale sorts civils the way it sorts building, only more sharply at the top. Below £1M of turnover, fewer than a third of firms make money; the £1–5M band is thin and only 43% profitable — big enough to carry plant and overhead, too small to absorb one bad job. From £5M the market turns healthy fast: 78% profitable in the £5–25M band, 87% at £25–100M, and every one of the four £1bn+ companies made money. Owning diggers and bidding frameworks is a terrible small business and a good big one.
| Turnover band | n | Profitable % |
|---|---|---|
| < £1M | 48 | 31% |
| £1–5M | 21 | 43% |
| £5–25M | 73 | 78% |
| £25–100M | 68 | 87% |
| £100M–1bn | 37 | 86% |
| £1bn+ | 4 | 100% |
The best-run mid-market operators
The table screens for profitable operators between £5M and £100M clearing at least a 4% margin — a bar set for contracting economics, where 2–4% is a normal good year. What passed, once the non-contractors are stripped out, is a tier of regional specialists who own a patch of network and keep working it:
| Company | What it is | Turnover | PBT | Margin | Headcount | Trajectory |
|---|---|---|---|---|---|---|
| Murphy Power Networks | Murphy group’s power-grid arm | £93.4M | £7.7M | 8.2% | — | — |
| Chasetown Civil Engineering | Midlands utilities civils | £83.6M | £5.4M | 6.4% | 130 | stable |
| W M Donald | Aberdeenshire civils and groundworks | £75.2M | £3.5M | 4.7% | 255 | growing |
| Excalon | power-network construction | £68.3M | £4.0M | 5.8% | 129 | — |
| Bateman Groundworks | East Anglian groundworks | £59.4M | £4.2M | 7.0% | 152 | stable |
| Carnell Support Services | motorway-network specialist services | £56.3M | £4.0M | 7.2% | 273 | stable |
| Galamast | network-infrastructure specialist | £54.5M | £6.6M | 12.0% | 196 | growing |
| C.R. Civil Engineering | rail and civils contractor | £52.1M | £5.4M | 10.4% | 173 | stable |
| S & R Construction | civils contractor | £45.9M | £4.1M | 9.0% | 61 | growing |
| DSD Construction | groundworks and civils | £44.6M | £4.4M | 9.8% | 140 | growing |
Tripod Crest (8.3%), Huyton Asphalt (8.3%) and GCU (11.3%) sit just behind on the same screen.
The pattern is a narrow trade held for decades: Carnell does specialist works on the motorway network, Excalon and Murphy Power Networks build grid connections at exactly the moment the grid queue is the country’s bottleneck, Chasetown and Bateman dig for the utilities in their home regions. Nobody here is national and nobody needs to be — the frameworks are regional and the client relationships compound.
What the screen also caught, and we removed: Dorenell Windfarm (37.3% margin) owns a wind farm — that’s generation revenue, not construction. Autolink Concessionaires (A19) (28.1%) is a road concession collecting availability payments on a motorway built decades ago. Bechtel Enka UK 2 (10.6%, 714 staff, +300% turnover) is a single-project joint vehicle of two global contractors, not a mid-market operator. Enercon, Wärtsilä Energy Storage and Nhoa are turbine and battery suppliers whose margins are equipment economics. And Granemore Group books £50M of turnover with nine employees — a structure, not a comparable operator. None of those margins mean anything next to a firm that employs its own gangs.
Growth, read with care
The genuine signal at the top of the growth table is Taylor Woodrow Infrastructure: +431% turnover to £159.3M and +145% staff, at a contractor’s clean 5.1% — a marquee civils name being ramped hard back into major-project work, hiring ahead of workload, which is the one growth pattern in contracting worth believing. Gransolar Construction UK (+581%, +100% staff, 9.6%) is a solar-farm builder scaling the same way.
Most of the rest needs a health warning. Freedom Fibre (+622%, −£25.4M on £4.5M of turnover) and Envision Energy International (−£52.9M on £12.3M) aren’t contractors having a bad year — one is an alternative fibre network building its own asset years ahead of its revenue, the other a Chinese turbine maker’s UK arm absorbing entry losses. QG Construction UK (+383% to a 41.5% margin while cutting staff 47%) has the signature of something landing in the accounts all at once rather than a business trading at those numbers. And Amentum Clean Energy’s +83% is, as above, a transfer, not organic growth.
Market structure
The top of this market is moderately concentrated — top 5 hold 31.1% of mapped turnover, top 10 hold 46.2% — much tighter than building (top 5: 18.9%), looser than road freight (38%). That fits the economics: national frameworks demand balance sheet and bonding capacity few firms have, but the work itself is regional, so a broad mid-market persists beneath the majors. Read the curve as directional — the top of it contains a turbine maker and a cost-plus JV alongside the true contractors.
| Share of mapped turnover | |
|---|---|
| Top 5 firms | 31.1% |
| Top 10 firms | 46.2% |
| Top 20 firms | 60.6% |
| Top 50 firms | 79.4% |
| Top 100 firms | 92.0% |
Ownership and vintage
Ownership tilts corporate — 141 corporate-owned against 104 individual-owned — the opposite of building’s even founder-family split, and the reason is visible in the giants table: much of Britain’s road and grid work is delivered by the UK arms of European construction groups (BAM, Ferrovial, and Vinci — which owns Taylor Woodrow, Ringway and, since January 2025, F M Conway — plus the groups behind Bylor) alongside listed UK players. If anything the corporate count understates it: ownership data can lag recent buyouts like Conway’s and McLeod’s. About 13% (32 firms) carry a Holdings/Group/Bidco-style name, and private equity is further in than the names suggest — R.J. McLeod sits inside Triton-backed OCU Group’s utility-contractor roll-up, and M Group, parent of the map’s utility-networks giant, has been CVC-backed since 2024.
The vintage profile is the mirror image of building, where the pre-1990 cohort dominates. Here pre-1990 holds just 38 of 251 firms, and the 2010s cohorts together (95 firms) outnumber everything before 1990 — because the work itself is new. Grid connections, wind-farm civils, battery storage and fibre didn’t exist as programmes twenty years ago, and each wave of infrastructure spending mints a fresh cohort of specialists to build it.
| Incorporation cohort | Firms |
|---|---|
| Pre-1990 | 38 |
| 1990s | 39 |
| 2000s | 63 |
| 2010–15 | 47 |
| 2016–20 | 48 |
| 2021+ | 16 |
What the map shows
- Infrastructure contracting out-earns building, structurally. The highways and utility-network giants cluster at 4–6% margins — Kier Transportation 5.8%, F M Conway 5.4%, M Group’s networks arm about 5.6% underlying (its 9.3% headline is flattered by a one-off provision release) — where building contractors of the same scale fight for 0–4%. Repeat framework work for the state and regulated utilities is the difference.
- The energy transition has contaminated the map. Turbine and battery makers’ UK arms, wind-farm owners, road concessions and cost-plus mega-project JVs now sit among the contractors; none of their margins are contracting margins, and comparisons that include them are meaningless.
- Cost-plus vehicles earn nothing on purpose. Bylor employs the 5,518-strong Hinkley Point C civils workforce and recharges £587M of it to the JV at cost, for £459k of profit — the margin sits with its parents, not in this entity.
- The mid-market winners own a narrow patch of network. Motorway specialist services, grid connections, regional utility digs — 6–12% margins earned by staying regional and specialist while the frameworks recur.
- Growth worth believing hires ahead of workload. Taylor Woodrow Infrastructure (+431% turnover, +145% staff at 5.1%) is the pattern; fibre and energy entrants posting huge losses are building assets, not failing at contracting.
- It’s a young, corporate-owned map. Pre-1990 firms are a small minority and European groups own much of the top — each new infrastructure programme mints its own cohort of builders.
Methodology and caveats
This covers the 251 UK companies in road, motorway and utility-network construction that publish a full profit-and-loss; several hundred more in the same trades are too small to report figures and don’t appear. Equipment makers’ UK arms, generation and concession vehicles and cost-plus joint ventures file alongside the contractors and are labelled and excluded from every margin comparison. Group holding companies and trading arms can both appear, so top-end totals carry some double counting; failed contractors exit the numbers entirely, so the map has a survivor bias; and large one-off gains or losses can reflect project completions, transfers or provisions rather than ordinary trading. The best-run screen uses a 4% margin bar, set for contracting economics. Figures are approximate and business-type labels are directional — verify any specific figure against a company’s own accounts before relying on it. This is analysis, not financial advice.