"I do not understand why the British government needs until October to decide whether to send the divorce letter to Brussels," he told German public broadcaster ARD late yesterday.
"I'd like it immediately."
He admitted that the EU had hoped Britain would stay but that now it was key to make the separation process as speedy and painless as possible.
"It is not an amicable divorce but it was also not an intimate love affair," he said.
British Prime Minister David Cameron said yesterday in the wake of the shock referendum outcome that he would resign his office in October and leave negotiations on the so-called "Brexit" to his successor.
