A small country with a decent road network does not need many seaports or airports and so it is with modern Ireland. Dublin Airport is by far the largest and it is located at the node of the national motorway network, attracting business from all over the island. Something similar happens with seaports. Dublin Port is easily reached off the motorways through the Dublin Port Tunnel and it dominates the Republic’s container trade.

About 85% of roll-on/roll-off traffic (Rosslare is the runner-up) and 73% of lift-on/lift-off traffic (Cork comes second) choose to ship through Dublin.

Rosslare and Cork have significant container volumes, Ro-Ro in Rosslare and mainly Lo-Lo in Cork, while Shannon/Foynes is important for bulk trades, including coal for Moneypoint and the Aughinish Alumina business. But Dublin is far and away the key port in the Republic: its most important competitor on the island is Belfast. This needs to be borne in mind in discussing the fall-out from Brexit. Some commentators have been arguing that any diversion of trade from Britain to continental Europe would see a shift in traffic to the southern ports, especially Cork and Rosslare, and some local politicians have been urging that road links to these ports be improved to prepare for such an eventuality.

All seaports need to invest from time to time to update equipment and to ensure that capacity is adequate and both Cork and Rosslare have ongoing capital plans. But neither should exaggerate the likelihood of an early bonanza.

Choice of routes

Shippers to the continent already have a choice of routings and the CSO figures show that Dublin dominates both Ro-Ro and Lo-Lo prior to any Brexit effect. There are plenty of direct container services to continental ports from Dublin and they are accessible by road from around the country. If there was some marked advantage for the southern ports, it is unlikely that these Dublin services would be popular. But does the geography not dictate that the southern ports must have an advantage, Brexit or no Brexit?

Unfortunately, the geography is not what you might think it is. Intuitively, Cork and Rosslare feel like they must be a lot closer to the continent than Dublin, but they are not. Table 1 below shows the distances from each to three important continental ports, in nautical miles.

Cork and Dublin are equidistant from the three continental ports shown.

While Rosslare has a small edge over the others it is rather modest: a container ship that can average 16 knots (a knot is one nautical mile per hour) would schedule 44 hours to get from Dublin to Rotterdam but would require 41 hours from Rosslare, saving just three hours.

It is a long way around Cornwall and the Scilly Isles, no matter where you start from. This saving has not been enough to persuade those currently serving continental ports from Dublin to add to the existing Ro-Ro services from Rosslare to France.

So what about the roads? The M11 towards Rosslare from Dublin is being upgraded but if your truck is already in Dublin, what’s the point? The M20 from Limerick to Cork was deferred during the recession but is now back on the agenda, but if you are starting out from Galway or Sligo, the trip to Dublin will be as quick or quicker. It is difficult to foresee a situation where the southern ports would suddenly become more accessible in any Brexit scenario. This sounds very counter-intuitive but take a look at a map (with the motorways marked) and the picture gets clearer.

It is not inevitable that Brexit will turn out so badly that the existing ‘‘land-bridge’’ traffic, across England to the Channel ports or the Eurotunnel, will be inhibited. It is even possible, in a benign outcome, that Irish-British trade can continue unaffected as well. If so, there might be no great change to existing flows and to the distribution between ports of Ireland’s seaborne trade. The biggest change would be in a recession following a no-deal Brexit, where Ireland-UK business overall would suffer.

There could also be a Brexit-induced downturn around Europe, where the economic recovery of the last few years seems to be running out of puff in any event. An extreme no-deal catastrophe, where truck drivers’ licences would be invalidated for UK journeys or where tit-for-tat border control wars broke out, is also possible.

But it is important to keep perspective and await clarity. Brexit could turn out badly or very badly – it is not going to turn out well for this country unless it is somehow scrapped. There should be no rush to spend money on roads or seaports until the fog clears.