Ultimately, we are back in the Brexit
Trilemma: The UK decided to exit Single Market and Customs Union – this would require a customs border between Northern Ireland and the Republic of Ireland – as this is seen contrary to the Good Friday Agreement, there will have to be a customs
border in the Irish Sea. Over the past four years, lots of myths have been created on how the UK can get around this (alternative arrangements, GATT article 24, Article 62 of the Vienna Convention on the Law of Treaties), but it seems Brexiters are back at
their favourite past-time: staging a tantrum in the sandbox and throwing out the toys: threatening that if Withdrawal Agreement (on which Johnson won the last election) is not being changed, they will simply undermine it with domestic legislation. As pointed
out by lawyers, this would simply end in a tit-for-tat with the EU, resulting in penalties and sanctions and worsening the relationship.