Britain will never accept a customs border between Northern Ireland and the rest of the United Kingdom, a government spokesman said on Friday, referring to a plan for the Irish border. The European Union’s chief Brexit negotiator said earlier that an economic arrangement to avoid a hard border between the Republic of Ireland and Northern Ireland could not be extended to the whole of Britain, as London proposes, Reuters reported. “The Prime Minister has been clear that we will never accept a customs border between Northern Ireland and the rest of the UK. We are also committed to maintaining the integrity of our own internal market,” the spokesman said, adding that this position will not change.