Finance minister Wolfgang Schaeuble dropped his bombshell in talks with German journalists on a flight from Asia, and apparently had the blessing of Angela Merkel, the chancellor. “When I put forward such proposals, you can take it as a given that the chancellor agrees,” he said.

Officials in Brussels reacted with horror. “If that is the demand, they are not going to get it. Nobody in the Council wants a new treaty right now,” said one EU diplomat.