Brexit will turn out to be a “blip” for Dublin Port, said chief executive Eamonn O’Reilly, despite trade with Britain plummeting and activity shifting to Northern Irish ports.

“We think Brexit is going to be a blip in the growth trajectory,” he told the Irish Independent as he outlined expansion plans for a site at Poolbeg on the south bank of the Liffey.

“This dislocation is a one-off. We think it’s permanent – unless Britain were to rejoin the single European market, and nobody thinks that’s going to happen.

“The effect of that is going to be to pause for a year – maybe a year-and-a-half – the growth in Dublin. But that is going to come back, we’re fairly certain of that.”

Port data shows container and trailer trade with England, Scotland and Wales dropping 21pc in the first nine months of the year.

Figures from the Economic and Social Research Institute paint a more dramatic picture, with goods imports from Great Britain plummeting 45pc since January at the same time as imports from Northern Ireland surged by 90pc.

Hauliers complain that Irish customs authorities are more heavy-handed than their EU counterparts, but Mr O’Reilly said controls in Dublin are working “very efficiently”.

Close to 90pc of ferries are now waved through the port without any physical or paperwork checks, with just under 3pc stopped for physical inspection in October. “The preparations for Brexit have been, I think, a great success,” Mr O’Reilly said. “The market adjusted. Part of that adjustment was the dislocation to the Northern ports.”

However, some firms continue to report long delays, with one food importer telling the Irish Independent recently the process was akin to bringing in “weapons of mass destruction”.

But despite the dip in trade with Great Britain, overall trailer and container trade in the port has fallen by just 0.5pc so far this year, with growth expected to return in 2022 and to recover to pre-pandemic levels by 2023.

It makes the expansion plans even more important, Mr O’Reilly said.

“There is inexorable growth in Dublin Port’s volumes. We can see it going back as far as 1950, and we think that’s going to continue for the foreseeable future. It can’t go on forever, but if we don’t do this project, we’re pretty certain there’s going to be a national port capacity shortfall by about 2030.”

The €400m scheme is funded by a bond issued to Allianz and a loan from the European Investment Bank. The new container terminal will be the country's biggest and the plan includes a new bridge over the Liffey, three public parks and 5km of cycle and walking routes.

Known as the 3FM project, it will allow the port to expand by up to a third of its 2020 volumes to accommodate the estimated 3.1 million trailers and containers that will be travelling through the port by 2040.

But Mr O’Reilly warned that more capacity will be needed after that date, and it wouldn’t be possible at the port’s current site, as that would mean filling in Dublin Bay.

Dublin Port is currently looking at a site in Arklow, while Drogheda Port Company has been working with developer Johnny Ronan on a €2bn project at Bremore, on the Dublin-Meath border. Mr O’Reilly said he welcomed the Bremore project as an add-on, but not as a Dublin Port replacement.

“We think the idea of building a new port there, into which you would move everything out of Dublin, is mad. We think that makes no sense. However, there will be more port capacity needed.”

Yesterday’s launch marks a kind of unofficial consultation phase of the project, with a planning application not expected until early 2023 and construction not due to start until at least 2026.

Views, ideas and suggestions should be sent by post to Dublin Port or emailed to 3fm@dublinport.ie by December 31.