IMMEDIATE UK Government intervention is needed to prevent more disruption to food supplies in Northern Ireland because of the post-Brexit trading rules, Boris Johnson has been warned.

Sir Jeffrey Donaldson, the Westminster leader of the Democratic Unionists, said supermarkets in Northern Ireland would face a “cliff-edge” at the end of March unless a grace period, in which EU certification rules are relaxed, was extended.

His remarks came in the wake of a letter sent this week by the bosses of Tesco, Sainsbury’s, Asda, Iceland, Co-op and Marks and Spencer to Michael Gove, the Cabinet Office Minister, over concerns about food supplies coming into Northern Ireland from Great Britain.

At PMQs, Mr Johnson assured Sir Jeffrey the Government would have “no hesitation” in triggering Article 16 of the Northern Ireland Protocol if necessary due to trade difficulties. This allows the UK or the EU to “unilaterally take appropriate safeguard measures” if its application leads to “serious economic, societal or environmental difficulties that are liable to persist”.

The PM referred to post-Brexit “teething problems,” that had led to images of empty supermarket shelves but stressed the Government would step in to resolve any issues if they became “disproportionate”.

But, unhappy with Mr Johnson’s reference to “teething problems”, Ian Paisley, the DUP MP for North Antrim, told MPs the people of Northern Ireland had been “screwed over” by the protocol.

During a later Urgent Question on the issue, Mr Paisley asked: “What did we do? What did we do to members on those benches over there to be screwed over by this protocol?

“Ask your hearts, every single one, what did we do? Because what has happened to this protocol; it has ruined trade in Northern Ireland and it is an insult to our intelligence to say it is a teething problem. Tell that to my constituents.”

During PMQs Sir Jeffrey insisted the supply issues leading to many empty supermarket shelves were directly down to the protocol, telling the PM: “We need direct Government intervention to deal with this now.”

Mr Johnson replied, saying goods were currently flowing effectively and in normal volumes between Great Britain and Northern Ireland.

“Yes, of course, there are teething problems and what I can confirm to him is that if there are problems that we believe are disproportionate then we will have no hesitation in invoking Article 16.”

However, SDLP MP Claire Hanna, who represents Belfast South, urged the Government to resist the DUP’s “reckless” calls to trigger the mechanism.

During the UQ exchanges, Mr Gove admitted the protocol “undoubtedly generates challenges as well as providing solutions” but stressed the Government was committed to providing “pragmatic solutions to any problems”.

Sir Jeffrey told the minister the problems for businesses and consumers were “graver than he recognises”.

He referred to people facing difficulties buying goods online from Great Britain with many parcel companies not accepting items from Northern Ireland because of the protocol while some businesses were facing post-Brexit barriers to getting spare parts and importing raw materials.

“Just this week, our steel manufacturers in Northern Ireland are being informed they face a 25 per cent tariff on some steel imports directly as a result of Northern Ireland Protocol because we can’t align with the UK quote on this.”

Calling again for immediate Government intervention, the MP for Lagan Valley added: “We do need steps taken to address what is now becoming a cliff-edge at the end of March for our supermarkets and others…We need an assurance that this is going to be resolved before the end of March or the grace period is extended further.”

Alistair Carmichael, the Liberal Democrat MP for Orkney and Shetland, told Mr Gove how he had lost count of the number of times the minister had given MPs “all sorts of assurances that there would be no barriers to free movement of goods between Northern Ireland and the rest of the United Kingdom”.

The former Scottish Secretary added: “It gives me no pleasure to reflect that that is manifestly now not the case. We do at least have a grace period to get things right and it is up to him to ensure that that happens.”

The concerns about the hold-up of goods in Northern Ireland came as the Irish Parliament heard how shelves in shops in Ireland would continue to empty post-Brexit because of the need to complete hours of customs paperwork.

Independent TD Verona Murphy said there had been “utter disruption” in the supply chain since the end of the transition period with truck drivers being stuck in ports for up to five days.

The former head of the Irish Road Haulage Association warned businesses were being damaged and further jobs would be lost in the coming weeks.

Irish officials have said around 30% of goods moving from Great Britain to Dublin are being held back over issues around documentation, with some requiring further checks. Trade volumes continue to be low in comparison with trade levels in previous years.

Ms Murphy told the Dail: “Utter disruption has ensued since January 1 at ports, in businesses, and in the supply chain. Food is being destroyed, businesses are failing, jobs are and will be lost.”

She added: “The consumer will pay a hefty price in their shopping basket if this is to continue, particularly those on low incomes.”

In response, Micheal Martin, the Irish PM, said Brexit essentially meant that seamless trade between the European Union and Great Britain was “a thing of the past”.

He told TDs: “That is a reality and there will be delays at ports because importing goods from Britain is now much more complex.

“The UK has left the single market and customs union and that creates additional burdens. There’s also some evidence emerging that many UK companies were not as prepared as they could have been to the realities of Brexit and the various additional checks and controls.”

He emphasised how Irish agencies were working “flat out” to ensure checks and controls were carried out as efficiently as possible, with over 1,500 additional staff working on customs.

Mr Martin added hundreds of containers were going through customs every day and the numbers were gradually increasing.