PM spoke to Merkel at 8 a.m. this morning - No 10 source says she said there could only be a deal if Northern Ireland stays in Customs Union, if not, then deal is 'overwhelmingly unlikely', no 10 (Johnson's office) says PM stressed to Merkel UK believes they had put forward a reasonable new deal, but with no desire to engage on EU side + this demand on NI staying in Customs Union a deal is 'essentially impossible'.