Britain still delivers world-class tunnel engineering. Crossrail proved it. Thames Tideway proved it. HS2’s Phase One tunnels continue to prove it.
The engineering is not the issue. The workforce is not the issue. The geology is not the issue.
What Britain no longer possesses is the system that makes infrastructure affordable: continuity, standardisation, coordinated planning, and institutional memory.
As a result, the UK pays some of the highest tunnel construction costs in the developed world — not because tunnels here are harder, but because the system around them has become dysfunctional.
1. The Lower Thames Crossing: £1.2bn Before Digging Even Begins
By early 2025:
- over £1.2bn had been spent on the Lower Thames Crossing (LTC)
- before construction started
Breakdown from published figures:
- ~£294m on planning, development consent paperwork and environmental assessment
- ~£369m on technical surveys and investigations
- ~£117m on land acquisition
- only ~£21m on early construction activity
This is not the cost of a tunnel. It is the cost of Britain’s process.
To illustrate the contrast:
- Norway’s Ryfylke Tunnel, a subsea road tunnel ~14.3 km long, cost in the hundreds of millions, not billions.
- The Sandoyartunnilin (10.8 km) in the Faroe Islands had an estimated £100m-level cost.
Different geology and labour markets, yes — but the order-of-magnitude gap is real:
Britain has spent more preparing LTC than some countries spent constructing entire subsea tunnels.
2. What Makes British Tunnels Expensive? Not the Digging — the System Around It
A tunnel is fundamentally predictable engineering:
- excavate
- line
- ventilate
- install mechanical & electrical systems
- ensure safety
- connect the portals
In Britain, the expensive part is everything before and around that work:
- multi-year planning cycles
- repeated consultation rounds
- overlapping regulators
- utility diversions negotiated in isolation
- shifting political commitments
- contractor risk premiums
- bespoke designs each time
- no standardised components
- no blueprint reuse
- long pre-construction phases
By the time a TBM reaches site, Britain may have spent 20–40% of total project cost without moving a single shovel of soil.
3. Why Costs Never Fall: Britain Cannot Learn From Experience
Countries with efficient tunnel delivery have three habits:
- Continuous building — crews and suppliers never disband
- Standardisation — each tunnel refines the next
- Institutional memory — lessons stick
In the UK:
- one megaproject is built
- the workforce disperses
- suppliers retool or shut down
- standards are not carried forward
- the next project starts at zero
There is no learning curve. No skill compounding. No supply-chain maturity.
Every tunnel becomes a first-time effort, priced accordingly.
4. HS2 Shows Britain Still Has the Capability — And How Quickly It Can Be Lost
HS2 Phase One includes around 32.5 miles of twin-bore TBM tunnelling.
The work has demonstrated:
- strong performance
- high-quality engineering
- well-managed tunnelling operations
- a large and capable skilled workforce
But political decisions — cancellations, pauses, shifting scopes — now threaten the continuity of that workforce and its supply chain.
If nothing follows HS2:
- the skilled tunnelling workforce will disperse
- apprenticeship momentum will stall
- suppliers will scale down
- accumulated expertise will fade
Rebuilding this capability later would be vastly more expensive than maintaining it now.
5. Utilities: One of Britain’s Most Persistent Cost Multipliers
A major driver of delay and cost escalation has little to do with geology and a great deal to do with how utilities are managed.
In many countries with strong delivery records:
- utilities are structurally aligned with national infrastructure planning
- diversion works fall within coordinated statutory frameworks
- timelines are consistent and enforced
In Britain:
- water, power, telecoms and gas utilities are separate commercial entities
- each negotiates diversions independently
- delays carry minimal institutional consequence
- no single body has overriding coordination authority
A tunnel can sit idle for months waiting for a single utility relocation — while costs accumulate across the whole project team.
6. TBMs Aren’t the Problem
A tunnel boring machine typically costs £8–20m. On a multibillion-pound project, that is negligible.
What inflates costs is the absence of:
- standardised TBM diameters
- consistent lining geometries
- repeatable mechanical & electrical systems
- domestic refurbishment capability
- reusable digital tunnel models
- predictable logistics
- long-term supplier ecosystems
When every tunnel is a bespoke design, every element must be re-invented.
Once a nation standardises these elements, costs fall quickly.
7. A National Underground Works Framework
Britain doesn’t need a new government agency or a centralised authority. It needs a framework that lets experience accumulate instead of evaporating.
A) A National Underground Works Register
A coordinated register of underground competence, administered jointly by:
- ICE (Institution of Civil Engineers)
- IET (Institution of Engineering and Technology)
- BSI (British Standards Institution)
- CSCS (as the competence-scheme operator)
This creates visibility of skills, portability between projects, continuity across sectors, and a foundation for long-term workforce planning.
B) Tunnelling-Specific CSCS Accreditation
Currently, most underground workers rely on a generic CSCS card plus project-specific tunnel safety training.
Introducing tunnelling CSCS categories — defined by industry bodies — would make underground competence portable, consistent and recognisable.
C) National Engineering Standards for Repeatable Tunnel Design
Standards set by ICE, IET and BSI should define:
- core geometry and lining profiles
- mechanical & electrical layout principles
- waterproofing and drainage requirements
- safety and evacuation architecture
- interoperable control systems
- material and performance tolerances
This enables blueprint reuse, modular mechanical & electrical systems, repeatable digital models, and far greater cost predictability.
D) Procurement That Rewards Workforce Continuity
Public and regulated clients — National Highways, Network Rail, water companies — can encourage continuity by:
- scoring bids higher for retaining trained tunnelling staff
- incentivising redeployment schemes
- supporting long-term apprenticeships
- discouraging reliance on short-term labour substitution
8. The Blueprint Effect: The Real Path to Cheaper Tunnels
Once a blueprint exists:
- designs repeat
- components standardise
- segment production becomes continuous
- mechanical & electrical systems become modular
- digital models carry forward
- safety systems are pre-validated
- logistics and sequencing become predictable
Costs fall not by cutting corners, but by stopping the reinvention of everything.
9. Britain Needs a Continuous Tunnel Pipeline — Across All Sectors
The UK already requires underground works on a national scale:
Transport
- metro projects
- relief tunnels
- high-speed links
- freight connections
Water
- sewer interception
- stormwater tunnels
- resilience and transfer tunnels
Energy
- deep cable routes
- nuclear support infrastructure
- hydrogen / CO₂ corridors
Digital
- secure fibre corridors
- resilience tunnels
Treating these as isolated projects guarantees perpetual high cost. Treating them as a 20-year underground works pipeline unlocks economies of scale.
10. The ELOXA View: Britain’s High Costs Are a Structural Choice
None of Britain’s tunnelling cost issues are inevitable.
They are the product of:
- fragmented planning
- isolated utilities
- absence of standardisation
- stop-start project cycles
- lack of competence visibility
- bespoke design on every scheme
- no framework to retain expertise
- no blueprint reuse
Britain has not forgotten how to dig. It has forgotten how to continue digging — how to carry forward the knowledge, people and systems that make infrastructure affordable.
Countries that build tunnels continuously see costs fall. Countries that rebuild capability from scratch see costs rise.
At present, Britain does the latter.
But with a National Underground Works Framework — standards, continuity, portable skills and a continuous pipeline — the UK can become one of the most efficient tunnel-building nations in Europe.
The choice is structural. The opportunity is real. The capability already exists.
It must not be allowed to disappear again.