Every now and then, various people seem to take the idea of a tunnel between the Isle of Man and Great Britain seriously. The idea makes no sense, it’s completely nonsensical, and it will never happen.
This is why.
The “Possible” Routes
Point of Ayre to Whithorn (~30km)
This route makes no sense because there is such a small population in South Western Scotland, and there’s no meaningful demand for travel from that part of the UK to the Isle of Man (or vice versa!) – let alone enough to fund a tunnel that would cost many billions of pounds.
Further afield, Whithorn is more than two hours drive from Glasgow, and more than four hours drive from Liverpool. If the Irish Sea train travelled at 100km/h, the undersea journey would take about 20 minutes – but would then require a lengthy journey to any significant city. A journey from Douglas to Liverpool via a train to Whithorn would take more than five hours, including driving from Whithorn to Liverpool. The previous train service to Whithorn closed more than 50 years ago.
Point of Ayre to Whitehaven (~50km)
Like Whithorn, Whitehaven is a remote town. Whitehaven is still three hours drive from Liverpool, but there is a minor train line that operates through the town: from Manchester in the South to Carlisle in the North.
A journey from Douglas to Liverpool via a train to Whitehaven would take at least four hours, including driving from Whithorn, which is still longer than the Mannanan’s Douglas to Liverpool sailing time.
Douglas to Barrow (~80km)
This was the route which was implicitly suggested in this nutty BBC article when the BBC mistakenly said that the Isle of Man is 50 miles (80km) from England, when Whitehaven (above) is much closer than that. Barrow is on the same minor train line as Whitehaven.
An Irish Sea train travelling at 100km/h would take around 50 minutes to travel from Douglas to Barrow, and then an onward drive to Liverpool around two hours and ten minutes, for a total journey of three hours – still a little longer than the current Douglas to Liverpool boat trip of two hours and forty-five minutes. Why spend billions to build a train tunnel that would take longer than the current boat?
Douglas to Blackpool (or Heysham) (~100km)
An Irish Sea train travelling at 100km/h would take around an hour to travel from Douglas to Blackpool, and then an onward drive to Liverpool around one hour and ten minutes, for a total journey of two-and-a-bit hours – marginally shorter than the current Douglas to Liverpool boat trip of two hours and forty-five minutes. It’s absurd to imagine spending well over £100,000 per Isle of Man resident to save half an hour’s travel to Liverpool.
Douglas to Liverpool (~125km)
This route would at least lead to a fast trip from Douglas to Liverpool – but would still take an hour-and-a-quarter at 100km/h. This route becomes unfeasible because of the extraordinary length of undersea tunneling required: it would be two-and-a-half times (!) longer that the world’s current longest undersea tunnel – the Seikan Tunnel in Japan.
The Seikan Tunnel in Japan took 17 years to build, and cost $US7billion. Assuming that we could build at the same cost-per-mile, this would cost at least £13billion (before we account for inflation, the likely exponentially extra cost for a longer tunnel, cost over-runs, and so on). That would be more than £150,000 for every resident of the Isle of Man. For £150k each, I’m very confident that the people of the Isle of Man would settle for an extra hour on the boat.
Possible tunnel routes from Britain to Ireland
This Wikipedia page has discussion of various ways to connect various islands in these Isles. Even those tunnels are unlikely to happen – but they are generally shorter and would attract much more traffic than a connection to the Isle of Man.