Schulz is hardly alone; even Merkel who was painted by the British media as keen to leave enough time to the UK to prepare their position is putting some limits: no informal talks until Cameron or BoJo triggers article 50 first.

EU Leaders Vow New Priorities After `Brexit' Vote - WSJ

"Until this has happened, no further steps can be taken," German Chancellor Angela Merkel told a joint press conference in Berlin with Italian Premier Matteo Renzi and French President François Hollande ahead of a dinner at the chancellery.