Germany's defence minister apologised for errors in his doctoral thesis today, saying he never intended to cheat.
Karl-Theodor zu Guttenberg, Germany's most popular politician and a potential future chancellor, now faces a criminal investigation for a plagiarism scandal putting his credibility on the line. He has been accused by newspapers of copying passages of his law dissertation without correctly attributing them in footnotes or bibliography.
The scandal, dubbed "Copygate", escalated today when public prosecutors in Bayreuth, where Mr Guttenberg wrote his law dissertation, said he was under criminal investigation for copyright infringement and signing a false affidavit.
"My dissertation was not plagiarised. I categorically deny this accusation," he told an impromptu news conference.
The 39-year-old aristocrat - full name Karl Theodor Maria Nikolaus Johann Jacob Philipp Franz Joseph Sylvester, Baron von und zu Guttenberg - is a rising star in Ms Merkel's conservative coalition, who tops popularity polls and has so far enjoyed doting coverage in the conservative media and gossip magazines.
Mr Guttenberg, who is married to the great-great-granddaughter of Otto von Bismarck, has recently had to fend off a number of setbacks as minister but his glamorous image had suffered little - until the plagiarism charges.
Chancellor Angela Merkel, who like many senior German politicians also holds a PhD, was seen backing her ally. "The chancellor has full trust in Guttenberg and his work," said a source close to Ms Merkel.
"His statement today shows that he is dealing responsibly with the questions on his dissertation."
Journalists had earlier walked out of a regular news conference with Ms Merkel's chief spokesman in protest after he had declined to comment on Mr Guttenberg's statement.
The minister said he would not use his PhD title until the result of an investigation by the University of Bayreuth, which has given him two weeks to respond to the allegations. "Without question, it does contain mistakes," Mr Guttenberg said of his thesis on constitutional law.
"I am responsible for each of those mistakes. But I did not cheat consciously at any time nor consciously attribute the authorship incorrectly at any point," said Mr Guttenberg.
He has been widely tipped as the next leader of the Christian Social Union, the more conservative Bavarian sister party of Ms Merkel's centre-right Christian Democrats, and has been regarded as a potential future chancellor of Germany.
The scandal comes at a difficult moment for Ms Merkel, whose coalition is recovering in opinion polls just ahead of seven regional elections in 2011, which start on Sunday in Hamburg.
It emerged after an academic read Mr Guttenberg's thesis and ran it through a plagiarism scanner before writing a review for the left-leaning legal journal Kritische Justiz, which has a circulation of 1,800.