Boris' ambitious new project has left many experts scratching their heads.
UK Government officials confirmed on 10 February that civil servants were examining a proposal for a crossing that would connect Ulster with Dumfries and Galloway, most likely near Portpatrick.
Prime Minister Boris Johnson called the bridge a “very interesting idea”.
Meanwhile Nicola Sturgeon said there were “more important priorities” and Ireland’s premier Leo Varadkar said it was “worth examining”.
However, there are several major obstacles to overcome for the project to become a reality. Here’s everything you need to know about the current plan.
Where would the bridge be located?
Two potential routes have been touted over the years for a possible crossing.
A Portpatrick to Belfast Lough link would be around 21 miles in length, while Antrim to Mull of Kintyre just 12 miles.
The latter option is routinely discounted however, as the road network from Campbeltown on the Scottish side would require significant upgrading through mountainous terrain, and lacks a direct rail service.
How much would the bridge cost?
According to the Prime Minister, the bridge would cost 'only £15 billion'.
However, various engineers and academics have already come forward to suggest that this price tag is essentially baseless since there is no actual design in place yet.
It has been suggested that the construction process would likely be fraught with problems and that, whatever the initial estimate, costs are likely to increase as the building progresses.
How long would it take?
Some estimates have claimed that the entire project could be completed within 15 years.
However, given the lack of concrete detail to the proposal as it stands right now, estimating the construction time has the same problems as trying to calculate the cost.
Will it ever actually happen?
Several experts have already expressed serious doubts as to the viability of such a plan.
Edinburgh engineer James Duncan pointed out that the stretch of water it would cross is over a thousand feet deep in places, meaning the bridge would require support towers of a size which had never before been constructed. ?
He surmised that the plan is about as feasible as 7 “building a bridge to the moon”.
He also highlighted how stormy those waters tend to be, adding a further set of safety concerns to the project.
Then there is the matter of Beaufort’s Dyke – an underwater trench which the Ministry of Defence has dumped over a million tonnes of obsolete munitions into. Link to Finlay’s explainer
In 1995, 4500 bombs from the Second World War washed up on Scottish shores as a result of it.
As the proposed bridge would have to cross the Dyke, this is another hazard to consider.
As Mayor of London, Johnson expressed other similarly ambitious plans for a “garden bridge” in the middle of the city, as well as one that would extend to a “Boris Island” airport in the middle of the River Thames.
Neither bridge was ever built.