Prominent news blog Fleet Street Blues (FBS) has been taken offline in the face of a libel claim by a PR agency working on behalf of Tulisa, the former N-Dubz star caught up in a sex tape scandal.

Press Gazette confirmed that the blog had claimed that PR agency Hackford Jones denied that its client Tulisa had appeared in a video of her engaged in a sex act. Hackford Jones maintains it did not issue a denial but stuck with "no comment" all the way through.

The blog has been taken offline, reportedly for investigation.

The post only briefly touched on the sex tape scandal and instead focused on PR firms. It did not directly name Hackford Jones.

Simon Jones, the agency's founder, told Press Gazette that a defamation action was under way against FSB.

He said: "It was some pretty outlandish claims on the blog. 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 tape came out on Sunday online and from the moment it came online all we did was issue 'no comment'. We obviously had a barrage of media calls all day Monday and all day Tuesday and we said to all media that were not making any comment whatsoever.

"There was no denial issued at any point about that sex tape and then Tulisa posted her own response to it on the Wednesday night."

He explained that the blog suggested his firm should be "hauled in front of the Leveson Inquiry" "and "struck off the PR list".

"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," he said.

"We very rarely take legal action in our profession.

"There seems to be so much rubbish written about this Tulisa story that you do get to the point where you think, 'I'm sorry I have to set the record straight."'