Fixed transport link between GB and NI ‘technical feasible’ but ‘impossible to justify’

While it is “technically feasible” to construct, maintain and operate a fixed link crossing between Great Britain and Northern Ireland, the costs would range from £209 billion to as much as £335bn, detailed analysis into the proposal has concluded.

Fixed transport link between GB and NI ‘technical feasible’ but ‘impossible to justify’

A concept sketch by architect Alan Dunlop of the Celtic Crossing as a sea tunnel

As part of the independent union connectivity review (UCR), Sir Peter Hendy was asked to consider the technical feasibility of constructing a fixed crossing across the Irish Sea or North Channel via a tunnel, bridge or combination solution, identifying the most viable solutions using current construction technology.

The study has also considered the land connections on both sides of the sea to ensure that a connection is technically feasible to either the strategic road or rail network or both.



Sir Peter Hendy concluded: “Whilst the economic and social effects would be transformational, the costs would be impossible to justify, given the Government’s already very significant commitment to long-term transport infrastructure improvement for levelling up, and the further likely significant expenditure which would result from the further studies I am suggesting in my main UCR report.”

The research team identified potential solutions and options to the provision of the fixed link and its associated connections to the wider strategic transport network. The study provides an indicative range of costs and timescales for construction, including high-level estimations of the carbon footprint during construction.

The evidence-based assessment concluded that cutting-edge, twenty-first century civil engineering technology would make it possible to construct either a bridge or a tunnel between Great Britain and Northern Ireland. A bridge crossing, however, would be the longest span bridge built to date. A tunnel would be the longest undersea tunnel ever
built given the limited gradients on which trains can operate, the route it would need to take and the depths it would need to reach. In addition, based on today’s technology and safety considerations, a tunnel crossing could only be constructed for railway use.

The need for a railway on either a bridge or tunnel would also require significant construction to connect it to the railway network at either end, introducing some complexity since the Irish railway gauge is different from that of Great Britain, the assessment added.



According to the report, the indicative cost estimate for the full route is £335bn for a bridge crossing and £209bn for a tunnel crossing.

Sir Peter Hendy said: “Future transport technological advances, particularly autonomous vehicles, could allow for different tunnel and bridge designs, which could enable the construction of a fixed transport link and approaches at a lower cost. For now, though, the benefits could not possibly outweigh the costs to the public purse. It is therefore my recommendation to government that further work on the fixed link should not progress beyond this feasibility study.”

He added: “Despite my recommendation, I am clear that this was an excellent question to ask. For many decades, politicians and engineers have debated this proposal, but have done so without the evidence to show whether it was possible and, if so, what it would take to do it. This is the first comprehensive, conclusive study on the subject since the idea was first mooted over 150 years ago.”

The independent Union Connectivity Review was launched in October 2020 to undertake how a detailed review of the quality and availability of transport infrastructure across the UK can support economic growth and quality of life.



Specific recommendations for improvements for connections across the United Kingdom include for improved connectivity with Scotland include:

  • Reducing rail journey times and increase rail capacity between Scotland and London, the Midlands and North West England by upgrading the West Coast Main Line north of Crewe and reviewing options for alternative northerly connections between HS2 and the West Coast Main Line
  • Seeking to work with the Scottish Government to develop an assessment of the East Coast road and rail transport corridor from North East England to South East Scotland, including improvements on the East Coast Main Line and the A1
  • Offering funding to support the upgrade of the A75 to improve journeys between Northern Ireland and Great Britain.

Sir Peter Hendy said: “My recommendations provide comprehensive, achievable and clear plans forward to better connect the whole of the United Kingdom, leading to more growth, jobs, housing and social cohesion.

“I welcome the enthusiasm shown by the Prime Minister and the government to my final report and I look forward to their formal response to my recommendations, which aim to spread opportunity and prosperity right across the United Kingdom.

“The UK government will now carefully consider the Union Connectivity Review’s recommendations in detail, working collaboratively with the Scottish Government, Welsh Government and Northern Ireland Executive to identify the solutions that work best for the people of the UK, and make tangible and meaningful progress as swiftly as possible.”

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