A University of Cambridge professor at the centre of a plagiarism row has resigned "with immediate effect". On Wednesday the university said it had launched an investigation into Professor Jason Arday "following new information" about his "academic qualifications and honorary appointments". It came after a series of media reports questioning some of his achievements and allegations of plagiarism in his PhD thesis. Arday said he had "concluded that the only way to bring this chapter to an end is to step away". Cambridge had initially described allegations made against Arday as a "vile campaign to undermine his credibility".