The Irish Sea Crossing conundrum – the technical challenge of bridging the gap between Great Britain and Northern Ireland

The idea of a crossing between Great Britain and Northern Ireland was previously mooted by Prime Minister Boris Johnson when he was Foreign Secretary.

A tall order it may seem, but it is now set to be given greater consideration as part of the Department for Transport’s union connectivity review.

The review, which is being undertaken by Network Rail chairman Sir Peter Hendy, will explore how connectivity across the UK can be improved to support economic growth and quality of life, particularly while the country faces a challenging recovery from the Covid-19 pandemic.

Its remit includes studying the feasibility of a fixed link across the Irish Sea between Great Britain and Northern Ireland (or possibly the Republic of Ireland). With Hendy due to produce an interim report by January 2021, and his final recommendations by next summer, the key engineering and funding challenges will be a crucial component of his work.

Civil engineers are capable of designing and building links over or under waters with depths between 50-150m, as would be encountered in the Irish Sea, even though solutions of this nature are at the very limits of current technologies. But where would it run, how much could it cost, and should it be rail or road, or both? In the attached technical briefing we asked two leading experts and ICE Fellows – independent bridge consultant Simon Bourne and independent tunnel consultant Bill Grose – for their thoughts.