A North Wales MP claims the UK Government’s “complete lack of interest in the security, viability and success of Welsh ports” could “spell disaster” for Holyhead as well as being a threat to Welsh devolution.

With a third of Holyhead’s freight traffic originating from Northern Ireland, Hywel Williams claims a failure to implement the previously agreed withdrawal agreement on the movement of goods between Wales and Northern Ireland, via Dublin, affects Britain’s second busiest roll-on roll-off port.

The partially replacement Internal Market Bill, unveiled on Wednesday, has also been described by Mr Williams as “dismantling Welsh devolution, but has been defended by the island’s MP”.

The government has already admitted the bill would break international law by rowing back on commitments made in the withdrawal agreement it struck with the EU last year.

Instead, ministers argue the measures will ensure “harmful” tariffs are not imposed on goods travelling from the rest of the UK to Northern Ireland if negotiations with the EU on a free trade agreement fail.

The First Minister has since waded into the row, however, claiming the bill represents “an enormous power grab,” granting the UK rather then devolved governments the powers to spend the new “shared prosperity fund” on infrastructure projects in Wales, Scotland and Northern Ireland.

“This Bill will do more to hasten the break-up of the Union than anything else since devolution began, we’ll oppose it every step of the way,” said Mark Drakeford.

Defending the bill, Michael Gove said the new spending powers would result in such decisions now be made in the UK, focusing on local priorities and accountable to Parliament.

But Arfon MP Hywel Williams says it would result in the UK Government becoming “the judge, jury and executioner when it comes to projects in Wales”.

Having tabled a written parliamentary question, Mr Williams also says the use of a Smart Freight System designed to regulate goods travelling to the EU would be “recommended but not compulsory” for goods between Wales and the Republic of Ireland, while not applying to goods between Great Britain and Northern Ireland, “creating confusion for hauliers.”

The use of the system will be compulsory, however, for goods travelling through Kent.

The Government says it has invited businesses to participate in user testing for the Smart Freight Service, continuing to engage with the Welsh Government on preparations for the end of the Transition Period.

But Mr Williams added: “The UK Government has failed to explain how its plans to break the law on the Northern Ireland Protocol will hit trade between Northern Ireland and Wales,”

“This is a huge concern for us in north Wales. Around a third of the freight arriving in Holyhead from Dublin comes from Northern Ireland.

“The UK Government seems to have no idea how their plans to break the protocol will affect us, caring nothing about the security, viability and success of Welsh ports.

“Its obsession, as ever, is with London and the south-east of England.”

But the island’s MP says the government remains “fully committed” to implementing the Northern Irish Protocol.

Virginia Crosbie went on to say: “I have received many messages concerning the impact of the UK Internal Market Bill and want to reassure them that the UK Government is trying to protect the delicate balance between the communities in Northern Ireland and avoid any risk to the Good Friday Agreement. 

“Holyhead is one of our major trading routes and I want to reassure the people of Ynys Môn that the UK Government absolutely recognises the importance of trade between Northern Ireland and Wales. 

“The UK Internal Market Bill is designed to ensure that companies can trade unhindered in every part of the UK as they have done for centuries. 

“These steps will help to ensure continued prosperity across all four parts of the UK.”