LORRIES heading for Northern Ireland could quickly back up on to main roads in Scotland if one encounters a problem with Brexit paperwork, a senior harbour executive warned.

Regulations around the movement of goods from Great Britain are under discussion following withdrawal from the EU.

Engagement with government customs authorities has been significantly ramped up in recent times, but concerns remain, port operators said.

The head of P&O’s Larne to Cairnryan ferry operation, Roger Armson, said: “The distance between check-in and the main arterial route to the central belt of Scotland is very short.

“You do not need to get much of a delay to start backing traffic up on to those routes.”

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Armson expressed concern if paperwork was not in order after a haulier turned up at the south-west Scotland port: “If a unit arrives without a valid goods movement reference there are no facilities in Scotland for that unit to park up. That is a bigger concern to me and something we are looking at very closely.”

About 200 lorryloads a day travel from the rest of the UK to supply Northern Ireland’s supermarkets. Stormont’s agriculture committee took evidence on Brexit planning from Northern Ireland’s port authorities yesterday.

Maurice Bullick, compliance director at Belfast Harbour, said: “There has been a long engagement with HMRC. It is only in the last short while that the engagement with HMRC has really ramped up.”

Under the protocol contained in the Brexit withdrawal agreement, Northern Ireland will remain in the EU single market for goods when the transition period ends.

That will require additional regulatory checks for animal-based food products entering Northern Ireland from Great Britain.

Port operators confirmed new screening facilities for goods arriving in Northern Ireland from Great Britain will not be ready for the end of the Brexit transition period, but said contingency measures would be in place.

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Negotiations between the UK and EU on a trade deal have covered areas like which goods are “at risk” of travelling from Great Britain into the Republic of Ireland via Northern Ireland and should pay tariffs.

Cairnryan is mainly served by the A77 and A75, which form two of the most important freight routes between Northern Ireland and the mainland UK.

Campaigners have repeatedly called for the roads to be improved, with traffic expected to increase post-Brexit. South of Scotland SNP MSP Emma Harper is to raise the issue at both Scottish and UK government level.

She said in June: “It’s time that further investment was made to improve both the roads, these are main arterial routes through the south-west of Scotland.”

Scottish Secretary Alister Jack insisted it is an issue for the Scottish Government.