The DUP are not happy with Theresa May over border plan

They've warned May not to "betray" them

The DUP has reacted angrily to a letter from Theresa May to DUP leader Arlene Foster, accusing May of breaking promises with regards to an Irish Sea border. British Prime Minister Theresa May wrote to the DUP stating that the European Union wants to put a border in the Irish Sea in the event of a no-deal Brexit. The letter, seen by The Times, was written in response to a letter sent by the DUP to May on 1 November that suggests the EU is looking for a customs border in the Irish Sea between Northern Ireland and the rest of the UK. "The EU ... want to maintain a Northern Ireland only ‘backstop to the backstop,’ in case the future negotiations are unsuccessful," May wrote in the letter. https://twitter.com/duponline/status/1060792032770379781 DUP leader Arlene Foster said the letter "raised alarm bells for those who value the integrity of our precious union and for those who want a proper Brexit for the whole of the UK". "It appears the Prime Minister is wedded to the idea of a border down the Irish Sea with Northern Ireland in the EU single market regulatory regime." The DUP said it is "totally unacceptable that there could be a Withdrawal Agreement which provided that Northern Ireland at any time in the future could be subject to the rules of the Customs Union or parts of the Single Market whilst the rest of the UK was not". May depends on the 10 DUP MP votes for a majority in Westminster and will likely need them for any vote on a deal she strikes with Brussels.