See this: https://www.theguardian.com/uk-news/...rthern-ireland
It was also in yesterday's Sunday Times. The Guardian version does not mention the likely cost (before the inevitable cost over-runs!). Neither does it mention the millions of tons of high explosives dumped in the Beaufort Dyke.
Given that the Channel Tunnel went bankrupt, despite being technically much less of a challenge, never mind being very centrally located for traffic, how can anyone not laugh at such a risible proposal?