The British government has suggested it could use the concept of force majeure to absolve it of its obligations to apply the Northern Ireland Protocol, RTÉ News understands.

Force majeure is a legal concept through which a party can demand to be relieved of its contractual obligations because of circumstances beyond its control or which were unforeseen.

The suggestion is contained in a 20-page letter the UK has sent to the European Commission.

The letter sets out a litany of factors which, the UK says, forced it to take unilateral action on how the protocol was being implemented.

The factors include the impact of the coronavirus pandemic, and the overall obligations of the protocol.

The letter, sent to the Commission on Friday night, was the UK government's formal response to legal proceedings initiated by the Commission on 15 March.

This followed a decision by the UK to unilaterally suspend some of the requirements of the protocol, and to extend a grace period without consulting the EU.

The letter criticises the Commission for taking legal action instead of "political dialogue" and rejects the notion that the UK’s unilateral moves on the protocol were in breach of the Withdrawal Agreement.

Two sources have confirmed the contents of the letter.

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A summary of the correspondence was conveyed to officials from EU member states yesterday.

The European Commission will take a number of weeks to decide the next course of action, which could result in Brussels opening formal infringement proceedings against the UK at the European Court of Justice.

It is understood the letter makes a series of accusations against the European Commission of failing to take account of unionist sensitivities in the application of the protocol, and of a refusal to be flexible in its approach.

It highlights the impact of parcels not being delivered, and of the impact of new requirements for people bringing pets - including guide dogs - from GB to Northern Ireland.

"This affects the principle…[that] the East-West dimensions are as important as, and indivisible from, the North-South context, the British-Irish [Good Friday] agreement, parity of esteem," according to one extract.

The Commission took legal action against the UK on the grounds that by unilaterally dropping some of the requirements of the protocol, and extending a grace period which had been mutually agreed by both sides last December, the UK was in breach of the good faith provisions of the Brexit Withdrawal Treaty.

The letter suggests a range of mitigating factors in order to justify the UK’s unilateral action, such as the Commissions move on 29 January - swiftly reversed - to invoke Article 16 of the Protocol.

It also claims the protocol had contributed to the rioting which erupted in Northern Ireland in April.

According to one extract, the letter states: "The recent disorder and localised violence in Northern Ireland is unacceptable and driven by complex and multifaceted factors. The perceived implications of the protocol on identity and Northern Ireland's links with the United Kingdom were at least, in part, among factors cited as contributors to that unrest."

The letter highlights the difficulties of setting up customs facilities during the pandemic.

In March of last year the EU suggested that the UK could extend the Brexit transition period on account of the impact of the pandemic, meaning more time to prepare for the Protocol.

However, at the time London ruled out an extension to the transition.

The letter also spells out that the UK reserves the right to trigger Article 16 of the Northern Ireland Protocol.

"The United Kingdom has not taken steps under Article 16 of the protocol but reserves its position in relation to its potential application to the present evolving situation in Northern Ireland," according to one extract.

The protocol was negotiated by the EU and UK in 2019 and requires checks and controls to be carried out on goods moving from GB to Northern Ireland so as to avoid such controls happening on the island of Ireland.

Despite the legal action, EU and UK officials have been working intensely at technical level to address some of the issues raised by the UK and Northern Ireland businesses.

These include the treatment of pets, including guide dogs, as well as medicines and food and plant consignments.