The Treasury and Department for Transport have been asked for advice on possible costs and risks of the project, according to Channel 4 News.
The idea has been floated previously by prime minister Boris Johnson when he was foreign secretary, with routes suggested either over a 20-mile stretch between Portpatrick and Larne or near Campbelltown to the Antrim coast.
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Proponents of the bridge think it could break the impasse over Brexit by removing the need for a border in the Irish sea.
But engineers have rubbished the idea, warning that it would be too expensive and impractical. In a letter to Business Insider, retired offshore engineer James Duncan said the plan as “about as feasible as building a bridge to the moon”.
“Many long bridges have been built, but none across such a wide, deep and stormy stretch of water,” Duncan said. He highlighted how on some parts of the route, the water was up to 1,000ft deep and any bridge would require around 30 support towers at least 1,400ft high to support the road deck above the deepest part and above ships. In total, he estimated, the bridge would need 54 towers “of heights never achieved anywhere in the world”.
Munitions dump
Perhaps an even greater challenge, though, lies in the Beaufort Dyke section, which was used in 1946 to dump munitions from the Second World War. “The Ministry of Defence estimates the total dumped at more than 1.5 million tonnes. There are no maps of their locations,” Duncan said.
He added: “No sane contractor or responsible government would consider building such a bridge, and because of the weather conditions it would probably have to be closed for considerable periods if it did.”
Last year when the idea originally surfaced, Gordon Masterton, past president of the Institution of Civil Engineers also warned of the engineering challenges and cost.
He told the Herald Scotland: “It’s not a new idea. There have been various ideas for bridges or tunnels between Scotland and Ireland down the years, although none of them has been properly costed or studied in any great detail.
“The project is not just the bridge, it’s the approach roads which in this case would go all the way back to the Central Belt. It’s good to have people thinking about large-scale projects which fire the imagination, but you have to focus on where the benefits will be and if there would be any value for money.”
‘Vanity project’
Meanwhile, procurement specialist Scape Group has surveyed British adults for their views on Johnson’s idea for the bridges and found that 58% saw the proposals as ‘vanity projects’. Four times as many Brits would choose to build underground systems for the UK’s most important cities over the Boris Bridges, it claimed.
Chief executive Mark Robinson said: “While the general public have not embraced the recent ideas proposed by Mr Johnson, encouragingly they do support targeted investment in less glamorous developments that will deliver economic benefits. And well they might. Poor transport infrastructure is hampering our productivity – road congestion alone costs our economy £9bn a year.
“Infrastructure is vital to the effective and efficient functioning of society. Investing in underground systems across the UK would be an effective way of creating a productive and functioning workforce – and levelling the playfield with our European peers.”
