The story started five years ago. A private investigator called Glen Mulcaire and the News of the World's royal editor, Clive Goodman, suddenly found themselves in deep water. They expected to get away with intercepting messages meant for the royal family. They were wrong. The pair went to jail, there was a minor bit of scandal and the paper's editor, Andy Coulson, resigned. Everything went back to normal.
Skip forward to 2009 , when investigative reporter Nick Davies published evidence that phone-hacking was actually extremely widespread at the newspaper — not the 'one rogue reporter' explanation the News of the World had relied on. The Met had a quick look at the allegations and decided that it wouldn't reopen the case.
The Guardian continued to publish details of high profile figures affected by the allegations - people as diverse as John Prescott and Sienna Miller. Eventually the various civil cases against the newspaper, from these people with deep pockets and plenty of spare time, began to drive the scandal onwards, even though most newspapers ignore it. Coulson, who had been taken on by David Cameron as director of communications in Downing Street, was forced to resign again, after he concluded that the ongoing coverage was complicating his political role.
And so it rumbled on. Everything changed last Monday, when the scandal went from one which concerned celebrities to normal families. The latest Guardian revelations suggest that journalists at the newspaper hacked into the voicemail of Milly Dowler, a teenage girl who went missing in 2002. They listened in as her family and friends left increasingly desperate messages. Then, when the system started to fill up, they did something that would change everything. They deleted the previous messages. This gave the family false hope, because they presumed it was their daughter still using the phone. It complicated the police investigation and potentially deleted important evidence.
Later the family granted the News of the World an exclusive interview, where they discussed their sense of hope - without any knowledge of the fact that it was that very newspaper's interference which had misled them.
Since Monday, reports have emerged that the families of several other high-profile victims have had their phones hacked into, as have the families of the victims of the 7/7 bombings.
What it means for the media
The phone-hacking scandal is now Fleet Street's expenses crisis. It's the moment when a practise which was widespread and internally accepted went public, horrifying everyone. It is the result of an increasingly desperate industry trying to make ends meet. With a dwindling print readership and plummeting advertising revenue, editors have had to make many journalists redundant while simultaneously trying to up their exclusives. This has created an increasingly brutal dog-eat-dog world in some newsrooms, where an employee's job security is based exclusively on their number of by-lines. It is highly unlikely that the News of the World was the only newsroom to indulge in the practise.
Without an effective regulator the problem has become much worse. The Press Complaints Commission (PCC) has few powers and is chaired by Paul Dacre, the editor of the Daily Mail. Such a patent conflict of interest would not be tolerated elsewhere but because it relates to the media there's no-one to report it.
Journalism's political influence is also under question. The widely-held political truth that party leaders must be friends with Rupert Murdoch to get into Downing Street may not be true after all. Political strategists noted how the Sun's endorsement of David Cameron failed to win him a majority — another sign perhaps of tabloids' dwindling fortunes. Ed Miliband's public call for Rebekah Brooks, chief executive of Murdoch's British operations, to resign showed that Westminster might be prepared to take a stronger approach to the media tycoon in the wake of the crisis.
With MPs increasingly calling for a full independent inquiry once the police investigation has run its course, the way in which journalism is conducted might be subject to fundamental and systemic change. The role of the PCC will almost certainly be firmed up, although anyone expecting an end to the culture of self-regulation is likely to be disappointed.
In the short term, the scandal is likely to complicate Murdoch's immediate business goals. His attempt to gain complete control of BSkyB, a political hot potato, is suddenly looking vulnerable. Media secretary Jeremy Hunt is being urged to pause the process while the scandal grows and Ofcom has said that it may look at whether chief executives at News Corp, the parent company, are "fit and proper" persons.
What it means for the police
The current police operation, codenamed Operation Weeting, has proceeded at a brisk and thorough pace. There have been several arrests at the News of the World and even at the Press Association. The case has expanded to cover allegations that Coulson paid off senior police officers. In a sign of how expansive the allegations are, the police are now understood to have contacted the families of every high-profile killing in the UK in the period in question. The Met is intent on cleaning up the situation.
But it was not always this way. Several Labour MPs are furious at what they suspect is a conspiracy between the Met and Murdoch's News International. There are allegations that the police didn't want to upset such influential tabloids and that senior officers lied to parliament about their earlier operations.
At the very least, the police failed to properly look into the evidence they had available to them during the original investigation, falling into line with the News of the World's insistence that it was the work of one rogue reporter. They then compounded this by refusing to reopen the case when the Guardian started printing reports of industrial-scale phone-hacking at the newspaper. That decision — which took a handful of hours to come to — fuelled suspicion that the police were desperate not to get involved.
Crown Prosecution Service (CPS) chief Keir Starmer then made matters worse for the Met when he told MPs that it was operating under a misleading assessment of what constituted phone-hacking. The Met insisted it had received CPS advice that the voice message needed to have been interfered with before the intended recipient heard it for it to have been a crime. The CPS insisted that it has said no such thing.
When the dust settles, the police will find themselves as much under the spotlight as the News of the World.
What it means for Downing Street
While the fire is currently focused on journalists and the police, Downing Street will be privately concerned that their time is coming. David Cameron hired Coulson as his communications chief after his resignation over phone-hacking from the News of the World. He was well aware of the allegations against him. He then defended him on numerous occasions and even made him head of communications at Downing Street while the allegations were on the front pages. Reports suggest that Coulson resigned at Murdoch's insistence, not Cameron's.
Meanwhile, Cameron will be regretting his decision to pay a social visit to Brooks during Christmas. That led to allegations of conflict of interest over the BSkyB deal. It will now provide ammunition to those questioning his judgement. Cameron's behaviour has been no different to any other prime minister since political strategists watched the Sun tear Neil Kinnock apart. The message was always: 'ingratiate yourself with Murdoch'. But Cameron went even further than most. By selecting Coulson for his communications chief he invited the Murdoch machine into the heart of Downing Street. He may be about to pay the price for it.