Simon Jones told Press Gazette that Hackford Jones PR was now pursuing defamation action, after Fleet Street Blues claimed that the company had issued a statement denying the authenticity of the singer's recently leaked sex tape.
The blog posting, which was reportedly removed soon after publication, focused on a response originally issued by Jones last August, when reports of private footage featuring the X Factor star first emerged.
"It was some pretty outlandish claims on the blog," Jones said. "At the end of the day we all work in the media and mistakes are always made, but the point is I'm happy to hold up my hands if I've made a mistake but I'm not happy to be accused of something I haven't done.
"This whole scenario with regard to this Tulisa sex tape denial comes out of the fact that people mistakenly attributed a quote to me with regard to the sex tape that wasn't issued. The sex tape came out on Sunday online and from the moment it came online all we did was issue no comment."
Jones explained that "no denial" had been issued to any media when faced with a "barrage" of calls early last week.
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Watch Tulisa's video statement about the leak below:
The anonymous journalist behind the blog has reportedly not yet responded to lawyers, while it has been restricted to invited readers only.
"Once that video came to light we're hardly going to be issuing denials that it was her, it's clearly her on the sex tape," Jones said, adding that "everyone in the industry knows that I look after Tulisa and it's an industry blog".
"The thing I take most affront to is we feel our reputation is on not lying to the media at all and we stand very strongly against lying to the media... so to be pulled out as a poster boy for PRs who lie, it really galled me," he said.
Meanwhile, Hackford Jones also confirmed that legal action is being taken against Sky News, who claimed that Contostavlos may have committed perjury while obtaining an injunction last week.
Above: Justin Edwards, MC Ultra, appeared in court this week to deny being behind the leak.
Explaining that the injunction was granted on privacy grounds, he told the website that the company had decided to act due to "so much rubbish" written about Contostavlos following the leak.
"There's been so much misreporting around this case which is funny in a way because in this age of Leveson when you think that everyone should be fact checking, even today people are still running stories based on hearsay," said Jones.
"You do get to the point where you think, 'I'm sorry I have to set the record straight'," he concluded.
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