David Cameron has refused at least 16 times to say whether he has ever discussed tobacco policy with Lynton Crosby, leading to the natural suspicion that he has. For Cameron, the perception that the government's stance on plain cigarette packaging could have been shaped  by a man whose company's clients include tobacco behemoth Philip Morris was a damaging one. But the Conservative strategist has now issued his own unambiguous denial. He said:
The Prime Minister has repeatedly and clearly said that I have never lobbied him on anything, including on the issue of tobacco or plain packaging of cigarettes.
What the PM said should be enough for any ordinary person but to avoid any doubt or speculation let me be clear. At no time have I had any conversation or discussion with or lobbied the Prime Minister, or indeed the Health Secretary or the health minister, on plain packaging or tobacco issues.
Indeed, any claim that I have sought to improperly use my position as part-time campaign adviser to the Conservative Party is simply false.
The hope among the Tories is that this will draw a line under the story (and they've certainly picked a good day to bury it) but the question remains: why didn't Cameron answer himself? Is his definition of a "conversation or discussion" different to Crosby's? Until the PM personally says that he's never "discussed" the issue with his strategist, suspicion is likely to persist.
Update: As expected, Labour has responded by drawing attention to Cameron's refusal to personally deny that he discussed tobacco policy with Crosby. The party has also noted that Crosby has said nothing about "any of the other policy areas" where he has business interests and has called for him to publish his company's full client list.
Here's the full statement from Michael Dugher:
This baffling statement raises more questions than it answers. David Cameron has refused to deny that he has had a conversation with Lynton Crosby about tobacco policy on at least 16 occasions. If Lynton Crosby is telling the truth, why on earth couldn't David Cameron say this himself?
The fact remains that David Cameron chose to bring a tobacco lobbyist into the heart of his Government, changed his policy on cigarette packaging and was then unable to give a straight answer about Lynton Crosby's influence. It's yet another example of David Cameron standing up for the wrong people.
It's striking that while Lynton Crosby has specifically denied discussing tobacco with the Prime Minister, he has said nothing about alcohol policy, or any of the other policy areas where his reported clients have interests. In the interests of transparency, Lynton Crosby needs to disclose his company's full client list right now.
The line from Downing Street, meanwhile, is that Cameron didn't want to get draw into a "running commentary" on what conversations he has and hasn't had with his strategist. But Crosby's intervention today has set a notable precedent. If he's to avoid further scrutiny, it's likely that he'll be forced to relinquish his business interests sooner rather than later.