By Jon Silverman
Legal affairs analyst
Lord Levy, one of four arrested, said the decision was a "relief"
Given that the cash for honours inquiry has been bedevilled by controversial leaks, it came as little surprise that its outcome was also leaked before the official announcement by the Crown Prosecution Service (CPS).
Likewise, it is a case where, at every stage, a political gloss has been placed upon legal or investigative decisions.
Lord Levy's assessment that he had been "exonerated" (in the words of his statement to the media) should be set against the carefully chosen terms used by the CPS lead, Carmen Dowd, who spoke of "insufficient evidence to provide a realistic prospect of a conviction against any individual".
In other words, no weighing of guilt or innocence. Only a calculation about the likelihood of evidence placed before a jury convincing it beyond reasonable doubt.
The explanatory statement issued on the CPS website is unprecedented in its detail and prosecutors will be under pressure in future high profile cases to match it when deciding not to press charges.
The CPS has put this material in the public domain to counter accusations that the inquiry was inordinately long and the decision on a prosecution unreasonably delayed.
It is clear that the original accusation, of cash being demanded for honours, would struggle to stand up given that the 1925 Honours (Prevention of Abuses) Act requires an "unambiguous agreement" to have been made between the parties to such corruption.
Without compelling evidence of such an agreement, the CPS felt unable to proceed to a charge.
As the website explains, some of the material gathered by the police, which may have looked powerful, might have been excluded from a trial because of legal rules.
That possibility also influenced the CPS decision.
Carmen Dowd was at pains to praise the "diligence and professionalism" of the police inquiry.
The officer who lead it, Assistant Commissioner John Yates, said he went where the evidence took him and that the inquiry would have been concluded much earlier if the issue of conspiracy to pervert the course of justice had not been raised.
It seems evident that it was this line of investigation which presented the police with their greatest challenge and led to claims of heavy-handedness.
Senior Scotland Yard officers strongly resent the accusation though, given the political sensitivity of the case, they expected it to be made.
The definitive police version of the way the inquiry was handled will probably have to wait for a report, which Mr Yates intends to place before the Metropolitan Police Authority.
The former chair of the MPA, Lord Harris, has said the police were under a duty to investigate the allegations thoroughly so it is unlikely that the Met will face criticism from its own political masters.
At Westminster, though, there is a lot of unresolved anger - not least from the Commons public administration committee which was blocked from pursuing its own inquiry by the criminal investigation.
This is a case in which there were no outright winners and whose lasting legacy may be fresh legislation to clarify exactly what political behaviour is acceptable and what should properly be the subject of police inquiries.