THE European Parliament has delayed setting a date to ratify the trade and security deal between the EU and the UK over concerns Boris Johnson will go ahead with plans to break international law.

On Wednesday, the European Commission accused the UK of breaking international law for a second time after ministers said the UK would unilaterally act to give Northern Ireland businesses time to adapt to post-Brexit rules.

Commission vice president Maros Sefcovic said the decision to exempt goods coming from Britain from checks amounted to a "violation" of the Withdrawal Agreement with the EU and this decision should have been agreed with the EU.

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The bloc previously accused the UK of breaching international law through amendments to the Internal Market Bill that would allow the UK to renege on obligations in the Withdrawal Agreement.

Sefcovic said in a statement about the new potential breach of international law: "This also constitutes a clear departure from the constructive approach that has prevailed up until now.”

The issues are around the Northern Ireland Protocol in the Withdrawal Agreement which was designed by the EU and UK to avoid a hardening of the border on the island of Ireland.

It achieved that by keeping Northern Ireland aligned to various EU rules, meaning checks are now required on goods arriving into the region from Great Britain.

On Thursday, Irish foreign minister Simon Coveney said the EU is as negotiating with a partner it “simply cannot trust”.

Coveney described the UK Government’s unilateral decision on the grace period as “very frustrating”.

“This is not the first time this has happened, that they (the EU) are negotiating with a partner that they simply cannot trust,” he told Irish broadcaster RTE.

Meanwhile, Northern Ireland's deputy first minister, Michelle O'Neill said the unilateral decision was a display of “extreme bad faith”.

She said the joint EU/UK committee on the implementation of the protocol should have been the forum for resolving issue around grace periods, rather than taking a “solo run” to unilaterally extend them.

“I think that the British government have again acted in bad faith and they have demonstrated by their very deed that they are untrustworthy, that they’re not reliable, that they’re not true to their word when it comes to a negotiation,” Ms O’Neill told an executive press conference in Dungannon, Co Tyrone.

“That’s form which the British government have demonstrated time and time again. In this case, I believe they’re on the wrong side of public opinion and they’re clearly on the wrong side of international law.

“Unilateral actions actually only help to up the ante and create even more uncertainty. What needs to happen is that all sides of the negotiation need to get round the negotiating table, sit down and talk about how we’re going to iron out the issues that are the reality of a post-Brexit world – the hardest possible Brexit.”

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Prime Minister Boris Johnson has said the issues are “eminently solvable” as tensions have been increasing around the UK Government's actions.

Speaking to broadcasters at Teesport, Middlesbrough, the Prime Minister added: “But what I can say is we are taking some temporary and technical measures to ensure that there are no barriers in the Irish Sea, to make sure things flow freely between GB and NI, and that’s what you would expect.

“Obviously these are matters for continuing intensive discussions with our friends.

“I’m sure with a bit of goodwill and common sense all these technical problems are eminently solvable.”