More than a thousand texts and messages were exchanged between News Corporation and the department for Culture, Media and Sport during the period when the Murdoch-owned company was bidding to take full control of broadcaster BskyB.
Speaking at the Leveson Inquiry on Thursday, News Corp lobbyist Fred Michel said that he received 257 texts from Adam Smith, the former special advisor to Culture Secretary Jeremy Hunt, between November 2010 and July 2011.
Between June 2010, when News Corp announced its BSkyB takeover bid, and July 2011, when it abandoned the plan amid outrage over the News of the World phone-hacking scandal, Michel said he made 191 telephone calls and sent 158 emails and 799 texts to Hunt's team.
Of these, more than 90% were exchanged with Smith, the inquiry was told.
"I am a compulsive texter, I would accept," said Michel. 'I apologise if my texts are too jokey sometimes," he added.
On one occasion Hunt sent Michel, who is French, a message thanking him for his praise at his performance in the Commons: "Merci, large drink tonight?" it read.
The lobbyist added that he had the "impression" that Jeremy Hunt was aware of details being passed on to him about the BSkyB bid.
Michel said he believed some of the "feedback" he was given by Smith had been "discussed" with his boss Hunt.
Smith, who quit after admitting his contacts with Michel were too close, is due to appear as a witness later on Thursday.
The lobbyist said he had the "sort of impression that some of the feedback I was being given had been discussed with the Secretary of State before I was given it".
Although he was not given legal advice on the nature of "quasi judicial" ministerial decisions, Michel said he knew he was not meant to have "direct discussions" with the Culture Secretary about the controversial issue.
He said he regarded the extent of contacts with Hunt's special adviser Smith and other officials as "uncharted territory".
"I think we had discussions on the fact that it was very important that the decision rested with the Secretary of State, that it was not appropriate to have direct discussions with the Secretary of State unless they were formal and minuted," he said.
"I was never of the opinion that it was inappropriate to at least try to put the arguments to or make representations to these officers."
The News Corp lobbyist said he quoted the views of "JH" in a series of emails to his bosses, including James Murdoch, but was referring to Hunt's team rather than the Culture Secretary himself.
He said: "I think it was a short-hand I decided to use, both because I was having a lot of conversations from the beginning of January (2011) with the office of the Secretary of State, but also because I was probably trying to be as quick and generic as I could be when I was writing them."
Michel agreed that Hunt's "quasi-judicial" role meant that there should also be no inappropriate contact with the Culture Secretary's civil servants or special advisers.
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But he insisted: "I don't think anything inappropriate ever took place."
The lobbyist said he sought to promote News Corp's bid with officials in the Department for Business, Innovation and Skills and the Department for Culture, Media and Sport, as well as with Labour and Lib Dem politicians.
"This was something I did across both departments and political parties as well, including the opposition," he said.
Michel told the inquiry he could not say whether Hunt or Smith supported News Corp's takeover of BSkyB.
Referring to the special adviser, he said: "Adam has always been a very warm, professional, available adviser, and always very diligent in his work with me.
"The only interactions I have had with him were always professional and reliable."
Robert Jay QC, counsel to the inquiry, asked him: "Is it your evidence that Mr Hunt was keeping an open mind, he was impartial, and would decide the bid on its merits at the appropriate time?"
Michel replied: "Yes."
The lobbyist played down a suggestion that he "spun" or "bigged-up" the information Smith gave him in order to reassure Murdoch about the progress of the bid.
But he admitted he might have tried to "keep morale up" at News Corp during the period until decision-making power on the takeover was stripped from Business Secretary Vince Cable and given to Hunt.
"I think my emails, as they were internal emails, were an accurate account of the conversations I have had," he said.
"Whether there was any exaggeration or spin, it depends. I would say perhaps during the period of when we were dealing with BIS (the Department for Business, Innovation and Skills), the morale was quite low because we had not much success on representation of this.
"Maybe I was trying to keep the morale up internally."
He will be followed in the witness box by Smith, who resigned as Hunt's special adviser last month after admitting he "went too far" in his dealings with Michel.
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The row led to calls for Hunt to resign as well, with Labour claiming that he acted as a cheerleader unbecoming the quasi-judicial role he had in overseeing the takeover bid.
Michel has already been forced to clarify that claims in his emails that he had spoken to Hunt had, in fact, meant that he had been in contact with someone in his office.
Labour's former business secretary Lord Mandelson, who has worked with Michel on a think tank in the past, advised Lord Justice Leveson this week to treat the lobbyists' claims with "some scepticism".
On Friday, the top civil servant at Hunt's Department of Culture, Media and Sport is also due to give evidence to the Leveson Inquiry.
Permanent secretary Jonathan Stephens was dragged into the BSkyB row when Hunt repeatedly told MPs that the civil servant had "approved" the arrangements for maintaining a line of communication with News Corp.
But Stephens declined to confirm that when he subsequently appeared before the Commons Public Accounts Committee.
He said in a later letter that he was "aware and content" of Smith's involvement.
Michel tried to organise a meeting between James Murdoch and Mr Hunt in November 2010 - before he was handed responsibility for the bid.
Smith responded that the permanent secretary advised that they should not meet personally.
In an email to Mr Murdoch, Mr Michel said: "My advice would be not to meet him today as it would be counterproductive for everyone but you could have a chat with him on his mobile, which is completely fine and I will liaise with his team privately as well."
Michel told the inquiry that he was not certain if the conversation took place, but it would have been a "quick call to the mobile to refer to the fact that they could not meet, apologise to each other and that is it".
The month before, Mr Michel emailed Mr Smith with a briefing memo for Mr Hunt on the BSkyB issues. The special adviser's answer stated: "Jeremy's response to this - 'persuasive'."
In the run-up to Christmas 2010 - around the time Mr Hunt took responsibility for the bid from Mr Cable - Mr Michel sent the Culture Secretary a text saying: "Have a great Christmas with the baby."
The two men had children who were almost exactly the same age.
Hunt replied: "Thanks Fred. All contact with me now needs to be through official channels until decision made."
Jay challenged Mr Michel over whether he had been exaggerating his contacts with Mr Hunt and his aides "to boost morale (at News Corp) or frankly to puff yourself up?".
He cited an example from September 2010, when questions were raised internally about reports that Mr Cable was intending to refer the bid for further scrutiny.
Hunt had sent the lobbyist a test message saying: "Don't know anything."
But Michel told colleagues in an email: "Jeremy Hunt is not aware and thinks it is not credible at all."
Michel denied today that he had been exaggerating. "I do not think I need to puff myself up," he said.
On Thursday Sir Jeremy Heywood, the cabinet secretary, defended his decision not to advise David Cameron that Jeremy Hunt be formally investigated over allegations he broke the ministerial code.
Earlier on Thursday, Conservative peer Lord Brooke said that Justice Secretary Ken Clarke finds getting through his ministerial red boxes "more trying" now, and may not remain in the political frontline much longer.