German defence minister Ursula von der Leyen, seen by many as a potential successor to the chancellor, Angela Merkel as leader of the conservatives, has denied accusations of plagiarism in the doctoral dissertation she wrote 25 years ago.

Germany’s education minister resigned today after a university decided to withdraw her doctorate, finding that she plagiarised parts of her thesis – an embarrassment for Chancellor Angela Merkel’s government as it prepares for elections later this year.