The Department for Transport (DfT) said the research into the feasibility of a fixed link cost £896,681. The idea of building a Scotland-Ireland connecting bridge or tunnel was finally scrapped in November 2021.

Network Rail chairman Sir Peter Hendy led the investigation, which found that a bridge would cost £335bn, while a tunnel would require a budget of around £209bn. His report concluded that the project “would be impossible to justify” as “the benefits could not possibly outweigh the costs”.

In addition to the huge expense, the inquiry also noted that the necessary work would be incredibly challenging.

The ill-conceived idea was initially announced in February 2020, as Boris Johnson sought to give his signature thumbs-up to an infrastructure project that would cement the legacy of his time in office. The bridge was predicted to run between Portpatrick in Scotland and Larne in County Antrim.

The DfT report described how Beaufort’s Dyke – an underwater...