No 10 is refusing to reveal the extent of Lynton Crosby's discussions with David Cameron about plain packaging, as a row over the lobbyist's links with the shelved policy continues to escalate.
Crosby's firm Crosby Textor has represented the interests of British American Tobacco in Australia.
Campaigners are suspicious of his possible influence in the coalition's decision to omit a bill introducing plain packaging for all cigarettes in today's Queen's Speech.
Downing Street said Crosby was a "political adviser" who will work with the prime minister in planning the Conservative party's election strategy for the 2015 campaign.
He does not have a desk in No 10 or even a pass and because he is not classified as working for an "external organisation" details of his meetings and conversations with Cameron will not be published.
The prime minister's spokesman said: "Mr Crosby hasn't lobbied the prime minister on anything... has there been any impact on the Queen's Speech? None whatsoever."
Labour leader Ed Miliband highlighted the issue in his response to the Queen's Speech when he pointed out former health secretary Andrew Lansley had said he thought children ought to be "protected from the start" from "glitzy designs on packets".
"That was the previous health secretary before they hired their new strategist," he said.
"The one whose company worked for big tobacco. And now what's happened? They've dropped the bill."
He added: "He can't provide the direction the country needs because he stands up for the wrong people."