https://www.irishpost.com/news/boris-johnson-wants-to-build-underground-roundabout-beneath-isle-of-man-to-link-northern-ireland-to-uk-204343

I thought this roundabout idea was merely a variation of the planned  tunnel. It is not. It is a completely different idea. Instead of the original plan of single link between Stranraer in Scotland and Larne in Ireland, now what they propose this “underground roundabout” alternative which consists of not one but three tunnels under the Irish sea!

https://www.newcivilengineer.com/latest/underground-roundabout-beneath-isle-of-man-proposed-to-link-three-irish-sea-tunnels-23-02-2021/

I love this part: "However, the UK press says that the idea is said to exist ’primarily in the mind of the PM’, according to one senior aide"

http://www.iomtoday.co.im/article.cfm?id=60704&headline=Boris%20Johnson%27s%20plan%20for%20tunnels%20to%20and%20from%20the%20Isle%20of%20Man&sectionIs=news&searchyear=2021