EU says Britain can leave backstop but Northern Ireland will have to stay

'The UK will not be forced into customs union against its will'

The European Union has turned down British demands for significant changes to the Brexit deal, returning an offer which will almost certainly be deemed unacceptable by Theresa May. Negotiators from the UK have been trying to find a legal way of getting around the Irish backstop arrangement, which has persistently proved problematic throughout negotiations. Now, the EU's chief Brexit negotiator, Michel Barnier, has made it clear this will only be possible if Britain leaves Northern Ireland inside it. Given that the Prime Minister has already flatly rejected the chance of agreeing to anything that would create a border in the Irish Sea, this proposal - which would create such a border - seems destined to fail, especially with the DUP also almost certain to reject it. Barnier took the unusual step of sharing the proposals in a series of tweets, posted on Friday afternoon. 'EU commits to give UK the option to exit the Single Customs Territory unilaterally, while the other elements of the backstop must be maintained to avoid a hard border,' the fourth of five tweets read. 'The UK will not be forced into customs union against its will.' Theresa May's Brexit deal will be voted on for a second time in the House of Commons on Tuesday. Should it be rejected again, she has warned that Britain may 'never leave the EU'.