Brexit and borders

Sir, – Theresa May rejects the idea that Northern Ireland could be included within the EU customs area , but warns of the “consequences for Ireland of a border in the Irish Sea” (News, March 6th).

However, there already is a border in the middle of the Irish Sea, and has been for many years: the Isle of Man is not part of the European Union, and yet is a member of the European Customs Union. As far as I can tell, the Manx, the British and the EU have all been comfortable with this arrangement. Is there any reason why it might not serve as a possible template for arrangements between the North of Ireland, Great Britain and the EU, post-Brexit? – Yours, etc,