The grainy images of Kate Moss snorting a white powder through a rolled £5 note seemed to leave the supermodel with little room for legal manoeuvre when they were unveiled nine months ago.
Stills from a videotape of an alleged late-night drugs session in a London recording studio followed a vow from Sir Ian Blair, Britain's most senior police officer, that "middle-class" drug users would feel the full force of the law.
As fashion giants abruptly ended their contracts with the Croydon-born model, senior Scotland Yard sources said they would not "turn a blind eye to celebrities" accused of drug use.
Fortunately for the 32-year-old millionairess and mother, the resolve of Yard and the Crown Prosecution Service to pursue high-profile suspects met its apparent match yesterday in an obscure legal loophole about drug classifications.
The CPS said that, despite being satisfied that there was an "absolutely clear indication" Moss was using an illegal drug and supplying it to others, including her rock star ex-boyfriend Pete Doherty, it would not be pressing charges.
The CPS revealed the refusal of Moss and other witnesses to explain her actions and the indistinct nature of the video images had ruled out any prosecution after a police investigation costing an estimated £250,000.
The pictures were published after the Daily Mirror paid a six-figure sum for them.
In a statement, Rene Barclay, director of serious cases for the CPS in London, said: "The footage provides an absolutely clear indication Ms Moss was using controlled drugs and providing them to others."
But the decision to take no further action was reached after a police expert was unable to tell whether the powder being chopped by Moss in the recording studio in Chiswick, west London, in September last year was cocaine, ecstasy or amphetamine.
A forensic examination of the scene also failed to specify which drugs had been used.
Mr Barclay said: "To obtain a conviction, case law establishes that the prosecution must prove beyond reasonable doubt the legal category to which the substance being used belonged."
The decision not to pursue the model, who has seen her earnings increase since the incident, will be a further embarrassment to Sir Ian, who said he wanted to see "a few examples made" of drug users with a high public profile.
The Conservative MP Anne Widdecombe said: "This is a question of the police and prosecutors not wanting to charge. They simply haven't wanted to do it - and you can always find a way out if you look for one. The message this sends out is horrendous."
The Yard insisted it had carried out a comprehensive investigation which was not focused solely on the actions of Moss but tracing a wider drugs chain.
Drugs and the law
Illegal drugs are divided into three categories in Britain, with increasing penalties for possession and supply according to the classification.
The classifications are decided on the grounds of the lethality, addictiveness and social damage caused. Heroin and crack cocaine, both class A, are considered the most dangerous drugs in widespread use in Britain. Under the Misuse of Drugs Act 1971, the penalty for supplying a class A drug is life imprisonment. The maximum sentence for supplying class B or class C is 14 years.
Police gathering evidence on the basis of the Daily Mirror videotape of Kate Moss had to ascertain whether the model was using cocaine or ecstasy, both class A drugs, or powdered amphetamine, which is class B. The decision not to charge Moss with possession or supply of a drug relates to precedents set by previous court cases, which make it clear that a prosecution can only succeed if lawyers prove exactly which category the drug in question comes from.
The Crown Prosecution Service said yesterday it would not have been enough for it to prove that the powder being snorted by the model was either cocaine (class A) or amphetamine (class B).Reuse content