Coulson gives evidence at the Leveson inquiry today
In evidence to the inquiry Coulson said he believed his employment by the political party as its press chief was based on his "communication skills and experience" and management skills, and that he made it clear his ongoing friendship with Rebekah Brooks "did not mean that the Sun would endorse us".
Coulson also told the inquiry he did not consider there to be a conflict of interest in taking the job, but acknowledged that he has since considered that the fact he held News Corporation Restricted Stock Units, awarded to him prior to his resignation, the second "tranche" of which became "vested" to him in August 2007 when he was working for the Conservatives, "could have raised the potential for conflict".
"Whilst I didn’t consider my holding of this stock to represent any kind of conflict of interest, in retrospect I wish I had paid more attention to it.
"I was never asked about any share or stock holdings and because I knew that l wasn’t involved in any commercial issues, including the BSkyB bid, it never occurred to me that there could be a conflict of interest."
Coulson, who went on to become director of communications for Downing Street when the Conservatives came into power, told the inquiry that while his experience working in the national press were likely to be "considerations" in his selection for the role with the Conservatives in 2007, the fact he previously worked for News International "was not specifically discussed as being an advantage".
The former News of the World editor also said he was "not especially close" to new editor Colin Myler and "understood his politics to be more sympathetic to Labour than the Conservatives".
As a result Coulson said he "told David Cameron, in one of our first discussions, that he should not expect an easy ride from the paper."
Cameron was also made aware that while Coulson was friends with Brooks "this did not mean that the Sun would endorse us", he added.
"I believe both of these warnings were confirmed by the mixed coverage we received in News International papers in the years ahead."
The Sun announced it would be backing the Conservatives in September 2009, with the News of the World also making the switch in March 2010.
"Through 2007 and 2008 the Sun remained at times doggedly supportive of Gordon Brown," Coulson added. "It was certainly clear to me it was going to be a long process."
Describing his original hiring by the Conservative party in his written statement, Coulson said it was completed via a phone call with the Prime Minister.
Coulson also confirmed that during this telephone call Cameron asked him "about the Clive Goodman case", in reference to the News of the World royal correspondent jailed earlier that year for phone hacking.
He added that "during the process of negotiation with the Conservative Party I had no contact with Rupert Murdoch, James Murdoch or Les Hinton."
He said "at some point" he informed Brooks "and other close friends" he was speaking with the Conservatives and was subsequently offered the position.
"I don’t recall any conversations at all that might have had a bearing on Rebekah making representations about my role or how my appointment might give an advantage to News International."