The political significance of the hacking scandal has been through many metamorphoses: first, it was no more than a cloud the size of a man’s hand over David Cameron; later, the hand curled into a fist, and Andy Coulson resigned as Downing Street director of communications in January 2011. In July of that year, the saga was reframed as Parliament standing up to corporate might, when Rupert and James Murdoch appeared before the Commons Culture, Media and Sports select committee. Throughout, Murdoch’s company, News Corp, had struggled to keep its bid for BSkyB separate from the mire into which the News of the World was slipping – a distinction which the Government respected. But the disclosure that the Sunday red-top had hacked Millie Dowler’s phone forced the bid to be dropped, the arrest of Coulson, and the appointment of the Leveson Inquiry. Ed Miliband enjoyed a moment of stardom, having shown undoubted guts in taking on Murdoch, and (ludicrously) the embarrassment of News Corp was described as the “British Spring”. When Leveson’s report was published in November 2012, the political story was reframed yet again as a battle between statutory regulation and the free press.  Subsequently, Cameron always insisted that he had been given “assurances” by Coulson. But Coulson’s clear memory, as he put it at the Leveson Inquiry, was this: “I was able to repeat what I’d said publicly, that I knew nothing about the Clive Goodman and Glenn Mulcaire case in terms of what they did”. His “assurances”, in other words, were limited to the single court case in 2007, when Goodman, the NoW’s former royal editor, and Mulcaire, a private investigator, were jailed for plotting to intercept voicemail messages left for royal aides. This was not the blanket guarantee Cameron heard, or chose to hear.  To which you may say: Coulson ought to have revealed to Cameron what he told the court in April – namely, that he had heard voicemail messages relating to David Blunkett in 2004, even if, as he claimed, he was not aware at the time that the material had been acquired illegally. Yet Coulson did make clear to Cameron over the years that any party leader hiring a former red-top editor is taking a calculated risk. “I wasn’t running a sweet shop, Dave,” he would say. After The Guardian reported in 2009 that News International had paid Gordon Taylor, boss of the Professional Footballers’ Association, to drop legal action, Coulson offered to resign. “You’ll get no quarrel from me,” he told Ed Llewellyn, the PM’s chief of staff. Determined to call it a day after the 2010 election, he was again persuaded by Cameron to follow him to No 10. Coulson later reflected that, had he parted company with Dave four years ago, “none of this” would have happened.  What is forgotten is how good at his job Coulson was, bringing maturity and professionalism to the party’s dilapidated communications organisation. This is not a fashionable thing to say, only five days after his conviction. All the more reason to do so. He was less given to outright spin than his Labour predecessors and rarely lost his temper. In the first months of the Coalition, before his departure, he was increasingly sought out by senior Lib Dems, including Nick Clegg, seeking discreet advice.  Cameron’s relationship with Coulson was an example of what the old News of the World would probably have called “Top Tory Toff’s addiction!” The Conservative leader became utterly dependent upon his adviser’s insights – not only because Billericay always has something to tell Bullingdon, but also because Coulson took to politics quickly and easily, and understood how to translate Cameron’s strategy into messages that would be picked up by the media. Inevitably, much has been made of his past in the Murdoch print stable and the mystique that held for Cameron – as if his comms director had only ever been on secondment from Wapping. But Coulson’s principal task was to get the Tory party on to our television screens.  Beyond his formal remit, Coulson became a confidant whom the Tory leader routinely referred to as “a genius”. Like many genial people, Cameron makes true friends slowly and very cautiously. Coulson was one of them. It was said that there were only three colleagues who could change Dave’s mind: George Osborne, Steve Hilton – and Coulson. As the attack intensified, the Tory leader grew more determined to hold on to his ally. Coulson knew that the game was up well before Cameron – a case study in what Margaret Heffernan calls “wilful blindness” in her marvellous book of the same name.  Now, General Hindsight – an elderly relative of Wilful Blindness – stomps through Westminster, honking, braying and stroking his damp moustache as if it had all been so obvious. Expect to hear a lot between now and the election about Cameron’s failed judgment and lack of ethical perspective. But the moral of the story, funnily enough, is not moral. It is psychological. Where friendship is concerned, we hear what we want, or often need, to hear, filtering out warnings even (as in this case) when they are issued by our friends themselves. As Cicero knew, no understanding of politics is complete without an understanding of friendship and its formidable power. And it is this power – rather than Murdoch, hacking, or Leveson – that has brought David Cameron and Andy Coulson alike to this wretched point.  'In It Together: The Inside Story of the Coalition Government’ (Penguin) is in paperback with new chapters
David Cameron was utterly dependent on his spin doctor&rsquo;s insights &ndash; and was   remarkably incurious about the precise details of his past