The former deputy features editor at the now defunct Sunday tabloid attributes the "get a story at any costs" culture amongst journalists to the paper's former editor Piers Morgan.
Giving his testimony to the Leveson Inquiry into phone hacking and media ethics, Mr McMullan made a succession of startling claims about the "at all costs" culture at the newspaper.
Mr McMullan pointed the finger at Mr Morgan, who became editor at the tabloid in 1994, who he alleged "set the trend" for untoward practices in the pursuit of the sales.
Mr Morgan, who went on to become editor at the Daily Mirror before pursuing a television career in the US, has yet to reply to the claims. A prolific twitter user, Mr Morgan has so far made no comment on the social media website.
Link to story and video:
http://www.telegraph.co.uk/news/uknews/leveson-inquiry/8923487/Paul-McMullan-Piers-Morgan-encouraged-unethical-practices-at-NOTW.html