The Social Democratic bigwig is expected to run against Mrs Merkel for the Chancellorship at Germany’s general election, but he is damning in his verdict of the EU’s future.
“Should that happen, our children and grandchildren would curse us.
“Because Germany is the biggest beneficiary of the European community – economically and politically.”
Mr Gabriel is hoping to take over the Chancellor’s role from Merkel at the next election
He said: “I once asked the Chancellor, what would be more costly for Germany: for France to be allowed to have half a percentage point more deficit, or for Marine Le Pen to become president?
“Until today, she still owes me an answer.”
The German election must take place before October 22, 2017, and, although Mrs Merkel has a slender lead in the polls, her popularity among the electorate is waning.
Her disastrous open door migration policy is largely to blame, with far right groups emerging all over Germany in the wake of a string of devastating terror attacks, the latest was committed at Berlin’s Christmas markets where asylum seeker Anis Amri killed 12 people.