The collapse of a high-profile murder trial over evidential questions poses uncomfortable questions for the police. But the case is of much wider significance, since it poses equally difficult questions for the prime minister, for his former press secretary, Andy Coulson, and for all those at News International who have stuck to their claim that no one in the company – bar one rotten apple – had any knowledge of illegal behaviour by, or on behalf of, its journalists.
Jonathan Rees, who was yesterday cleared of murdering his former business partner, Daniel Morgan, is a private investigator of a particularly unpleasant and vindicative kind. In the late 1990s he was working for the News of the World, paid as much as £150,000 a year to use his dark arts to illegally trawl for personal information on the paper's targets.
The work, which included bribing police officers, came to the attention of Scotland Yard's anti-corruption team, who bugged his office for six months. In December 2000 his newspaper work – which included work for the Mirror Group – came to a sudden and enforced halt when he was jailed for seven years after being caught planting cocaine on a woman. The aim was to discredit her prior to divorce hearings
Rees was one of four private detectives – all of them now convicted criminals – who are known to have been retained by the News of the World, apparently without the knowledge of a single executive.
Rees's exploits were certainly no secret.
They were written about in two articles published by the Guardian in 2002, while Rees was in prison.
One of them named a News of the World executive, Alex Marunchak, who had been caught on tape discussing payments of thousands of pounds. Despite all this – Rees's links to corrupt police, his prison sentence, the publication of his links to, and payment by, the newspaper – he returned to work for the News of the World, now edited by Andy Coulson, in 2005 after he had left prison .
Rees was charged with murder in 2008, which meant that no newspaper could, until today, name him.
But both David Cameron and Nick Clegg knew of the background to the story in early 2010, well before they entered Downing Street.
The new prime minister chose to ignore it, appointing Coulson head of communications at Downing Street in May 2010.
It was an extraordinary piece of bad judgment, and surprising that Clegg apparently did not demur or distance himself in any way.
Did no one carry out any official vetting before Coulson was allowed across the doorstep of No 10? Or did Cameron and Clegg want the former Murdoch editor so badly that they pretended not to know, and ignored the ticking time bomb which exploded yesterday?
Meanwhile, what of Acting Deputy Commissioner John Yates, who was so quick to assure the world that there wasn't much to the phone-hacking stories uncovered by journalists on this and other newspapers? He has hired one of the UK's most notorious libel firms to warn off this newspaper for reporting the claim that he misled parliament.
In a Commons debate this week, Chris Bryant, MP for Rhondda, made the direct accusation that Yates did, indeed, mislead two parliamentary select committees. Moreover, it was alleged that Scotland Yard has known for five months that its evidence was incorrect. The two committees involved should, as a matter of some urgency, invite the police to explain its position.
Until now most of the attention around phone hacking has centred on the activities of Glenn Mulcaire, who was jailed in 2006 for his work on behalf of the News of the World.
Rees was actually paid more than Mulcaire and is alleged to have deployed a wider armoury of illegal methods to acquire information for his Fleet Street clients.
Now that his name is no longer protected by court restrictions, another chapter in this disturbing saga of intrusion, power and criminality can be written.