Comedian whose phone was hacked says he was motivated to sue NoW by seeing Andy Coulson 'at the heart of power'

Steve Coogan recalls clearly the moment he decided to sue the News of the World. "What motivated me was seeing Andy Coulson [the paper's former editor] gaining a modicum of respectability standing next to David Cameron."

The actor and comedian adds: "I remember thinking 'Andy Coulson should not be at the heart of power.' That was my gut instinct. That man shouldn't be there."

Over lunch in New York, where he is filming an adaptation of a Henry James novel, Coogan says: "Two years ago I rang my publicist and said 'Look, there's some information that my phone may have been hacked.' I was told: 'That story's gone away, it's not going to come back and Coulson's at the heart of Downing Street now, he's surrounded by a ring of steel.' "

Despite the warning, Coogan started legal action, becoming one of a handful of celebrities to do so. His legal battle has played a pivotal part in the fight to uncover how widespread the practice was at the NoW, giving him a leading part in the revolt against tabloid excess. As Coogan developed his own case, he obtained some crucial evidence about related hacking activities undertaken by Glenn Mulcaire, the private investigator employed by the tabloid.

Mulcaire was forced by the high court to write to Coogan's legal team revealing who at the title ordered him to hack into mobile phones belonging to a group of public figures in the middle part of the last decade, including the fashion model Elle Macpherson, the politician Simon Hughes, the publicist Max Clifford and a football agent, Sky Andrew.

Coogan is barred by the terms of the court order from discussing the contents of the letter, but it is widely expected to reveal that Mulcaire took instructions from more than one person at the NoW. If so, it will provide the most compelling evidence yet that the News of the World's "rogue reporter" defence was a ruse designed to disguise the true extent of phone hacking at the paper.

Coogan says News Corp's senior executives must be held to account for that. "The culture of the people on the shopfloor is reflection of management," he says. "It always is. So it may be that certain people haven't committed crimes, but there's a cultural culpability."

He believes the hacking affair is symptomatic of a wider malaise afflicting the tabloid press, and believes now is the time to tackle a culture of what he calls irresponsible journalism.

"We all know it's not one rogue reporter but it's not even an aberration," he says. "Hacking into a victim of crime's phone is a sort of poetically elegant manifestation of a modus operandi the tabloids have."

He concedes that view is coloured by his own treatment at the hands of the News of the World and some of its rivals, which have written stories in the past about his drug use and sex life.

"I got my arse kicked," he says. "Is it part of a sort of personal vendetta? That's certainly what motivated me in the first place, I won't deny that."

He says that Coulson personally orchestrated an unsuccessful attempt to trick him into admitting he had slept with a woman, which was foiled after Coogan was tipped off by the News of the World's former showbusiness editor Rav Singh.

"He had this dancer in his office once that I'd spent the night in a hotel with … [she was] calling me [from his office] to try and get me to admit to various things. This is not illegal, but it shows you the character of the man. The point is that this is the kind of thing he does. That's not to say he knew about hacking. We don't know this yet. We'll learn about all the details of that in the inquiry."

Critics might argue that the story about the dancer also reveals much about his own character, but Coogan insists tabloids have no right to delve into his personal affairs.

"What happens in my private life is none of your fucking business," he says. "I'm an entertainer. I don't go round saying I'm a paragon of virtue, so that is clearly not in the public interest."

Nor does he accept the argument that curtailing the media's freedom to write about the peccadilloes of the rich and famous is tantamount to censorship.

"It serves certain people's commercial interests to characterise what's happening as an attack on the freedom of the press and it's not," he says.

"It's about responsible journalism. The tabloids operate in an amoral parallel universe where the bottom line is selling newspapers.

"It's like blaming a scorpion for not being moral. They just sting people. That's what they do. Sometimes they might sting someone who deserves it. But it's not through any moral imperative.

"And this idea that for every 20 stories they do about a pile of shit, they do one story that has some sort of nobility to it – I don't buy it."

Coogan says News Group, the News Corp subsidiary which owned the paper until it closed in July, had offered to settle his case.

"It wouldn't have covered the costs but it would have taken the sting out of what I'd spent," he says. The action has so far cost Coogan more than £100,000.

But he refuses to speculate about whether James Murdoch, chairman of the News of the World's parent company, News Corporation Europe, should stand down. And he will not talk about Coulson's future, although he is clearly not losing much sleep over their fate.

"If my conduct is fair game for them then their conduct is fair game for people like me to comment on," he says. "It's a democracy and I'll have my say."

He wants to ensure that the hacking story remains centre stage, and plans to use his profile to ensure News Corp does not escape further scrutiny by spinning out the civil actions in the hope the public will lose interest.

"[They are hoping] there will be some big disaster or something that'll knock it off the front pages and hopefully no one will care anymore. And I will do everything in my power [to prevent that].

"Because I'm a more populist person and I reach a more generalised audience that goes beyond broadsheets I can help keep it in the popular imagination and I will do everything in my power to keep it in the popular imagination."

He recalls a conversation with Martin Sixsmith, the former civil servant and journalist, with whom he worked on the film In the Loop.

"He said to me: 'You could walk away from this but you won't – you'll probably want to have a fight because you're a bloody-minded northerner.' And I thought 'Yeah, he's right.' "