Sunday Mirror 'used trickery on MP sting story,' says Hacked Off
The Sunday Mirror says its investigation targeting a number of MPs through social media, was in the public interest.
The paper said it had been investigating inappropriate use of social media by MPs.
The subsequent story led to the resignation of government minister Brooks Newmark, amid allegations he sent explicit pictures of himself to an undercover journalist.
However, Brian Cathcart from the campaign group Hacked Off, claims the Sunday Mirror used "trickery", and said the paper "had a lot of questions to answer".