Implications Of A 'Chunnel Tunnel' Between Ireland And UK Mainland.

[SlickWilly]

This was actually originally mooted in the 19th century and occassionally comes up as a possible investment project. The current suggestion is to build to a bridge to the Isle of Man from Ireland and then onto the UK mainland. I don't know if it would ever by economically feasible or viable, but there are longer bridges between Danish Islands and of course there is the magnificent bridge crossing between Denmark and Sweden.
You would then have no non land border within the EU. BTW I would love to see it!

[Jape]

There's a little tidbit of history from Roy Hattersley about the dying days of Callaghan's Labour government. Desperate to win the 1979 vote of no confidence, amongst other things Labour went cap in hand to the Ulster Unionists via Enoch Powell. Alienated from the Tories he said he would be happy to support Callaghan as long as he promised the building of just such a channel tunnel to Northern Ireland and gave priority to Ulster contractors.

It strikes me as a political creation, so maybe if something like the above got put into place, it could happen?

[Meadow]

I'd love to see an industrial TL where events are shifted to make this kind of thing commonplace. JFC Fuller as PM has been mooted by EdT a few times IIRC, and I think that contained a Channel Bridge. Oh yes.

[Rubberduck3y6]

Wikipedia article on this.

I think the political effects (and funding) would partly depend on whether the tunnel was built between GB and Northern Ireland or GB and the Republic. I think the Holyhead-Dublin route would be the best, especially if it was linked to a HSR network.