The ink was not yet dry on EU leaders' deal to give Britain a hard-fought, second delay to Brexit until November when some diplomats and officials in the bloc grudgingly conceded: This may well not be the last extension.

The Wednesday evening European Union summit ran into the wee hours of Thursday after staunch opposition from French President Emmanuel Macron to a longer postponement of Brexit swung the balance in favor of the Oct. 31 compromise.

European Commission Secretary-General Martin Selmayr coined a new Twitter tag: #29MarchMeans12AprilMeans31Oct — a quip on how Britain had been due to leave the EU last month, then got a reprieve recess until Friday and now a new delay, months longer than London had sought.