Customs checks required as part of the EU withdrawal agreement were postponed by three months at the end of June to allow London and Brussels time to find a solution to long-lasting frictions. However, there is thought to have been no contact between Brexit minister Lord Frost and his EU counterpart since July.

       While discussions have continued at a technical level among officials, the lack of political engagement has stalled talks.

       With less than a month until the end of the extended grace period, the two sides look set to once again publicly clash over the Brexit deal agreed in 2019.

       Under the terms of the Protocol, customs checks are required on chilled meats, such as sausages, that are travelling across the Irish Sea from Britain.

       The UK has accused Brussels of being overly purist in its implementation of the Protocol checks, claiming they are having a detrimental impact on the UK's internal market.

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       For its part, the EU has demanded the Brexit deal be implemented in full.

       Earlier this year the UK threatened to take unilateral action to extend the grace periods in order to ensure goods could continue to pass easily from mainland Britain to Northern Ireland.

       Brussels reacted angrily to the suggestion and warned it would take retaliatory action if such measures were adopted.

       A similar standoff is now likely in the comings weeks.

       Confirming there had been no progress in talks, an EU official told The Telegraph: "This has been the quietest summer in the five years of Brexit.

       "Maros Sefcovic and Lord Frost have not even spoken to each other since July."

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       Negotiations to find a breakthrough to the impasse on the Protocol are expected to get underway again next week.

       Lord Frost and Mr Sefcovic are expected to talk via the phone about the current situation.

       In July the UK unveiled a series of proposals which it said would help to ease the problems caused by the Brexit agreement.

       It included removing all customs checks, instead introducing light-touch checks of business supply chains and removing the role of the EU Court of Justice in overseeing the Protocol's implementation.

       The EU immediately rejected the suggestions and said the Protocol was not up for renegotiation.

       Mr Sefcovic said at the time: "The Protocol on Ireland/Northern Ireland is the joint solution that the EU found with the Prime Minister, Boris Johnson, and Lord Frost – and was ratified by the UK parliament – to address the unique challenges that Brexit, and the type of Brexit chosen by the British government, poses for the island of Ireland."

       As it stands, the grace period of customs checks will come to an end on October 1.

       Lord Frost has not ruled out triggering Article 16 of the Protocol, the legal means to abandon terms of the treaty, if a solution is not found.