THE EU is launching legal action against the UK Government due to an alleged breach of the Brexit agreement. 

Downing Street is expected to receive two letters from the European Commission setting out the legal challenge.

The first document is said to be a formal notice, which will prompt an infringement procedure due to an alleged breach of EU law.

The second was described by Brussels insiders as a "political" letter, claiming the good faith provisions of the Brexit Withdrawal Agreement have been breached.

The legal letter could see the UK Government taken to the European Court of Justice, while the political warning may trigger an arbitration process under the dispute settlement mechanism within the Withdrawal Agreement.

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The dispute centres on Number 10's unilateral decision to allow businesses in Northern Ireland more time to adapt to post-Brexit rules.

The Northern Ireland protocol, which is part of the Withdrawal Agreement, is designed to negate the requirement for a hard border on the island of Ireland.

Under the protocol, checks are carried out on goods travelling from Britain to Northern Ireland to ensure they adhere to EU requirements.

However, the full application of the measures has been delayed by a grace period introduced by the UK Government, which insists it is necessary to keep shelves stocked in Northern Ireland. Earlier this month, Tory ministers announced the arrangement would be extended, angering counterparts in Brussels.

The EU says that by extending the grace period Downing Street has breached both the rules of the Withdrawal Agreement and, potentially, international law.

The UK Government denies its actions are unlawful.

Cabinet Office minister Lord Frost and EU Commission vice president Maros Sefcovic are understood to have spoken today.

Downing Street is yet to receive a letter notifying it of the infringement proceedings on Monday morning, but one is expected to be dispatched later in the day.

Prime Minister Boris Johnson said the extensions are “very sensible”, with the Government denying there has been a breach of the protocol.