In a statement issued this afternoon, police said the long process of constructing a psychiatric report on Mr Smith-Voorkamp was to blame for the six-month legal battle.
Superintendent Dave Cliff, who was Canterbury district commander at the time of Mr Smith-Voorkamp's arrest, said the independent report received last Thursday concluded Mr Smith-Voorkamp had diminished responsibility for the charges leveled against him.
"Police consider that when taking this into account, the crown prosecution guidelines "public interest test" is no longer met and therefore leave was sought to withdraw both charges."
Mr Davis had alleged Mr Smith-Voorkamp was elbowed in the head at the time of his arrest.
But Mr Cliff said Mr Smith-Voorkamp had only received "a bang to the side of his face" when he was forced to the ground during his arrest.
"The pair were affected by alcohol and potentially drugs at the time of arrest."
Mr Smith Voorkamp's lawyer Jonathan Eaton said his client had never taken drugs and only consumed two glasses of wine on the night of his arrest.
Psychiatric reports had found extreme stress causes Mr Smith-Voorkamp to stutter and become difficult to understand, he said.
"Alcohol was not a relevant factor. If officers had described him as intoxicated they were wrong. He had two glasses."
Mr Eaton said Mr Smith-Voorkamp was not interested in pursuing assault charges against the officers who carried out the arrest.
"He doesn't want anything to do with the police at the moment."
Police were made aware of Mr Smith-Voorkamp's mental condition within weeks of his arrest and received an official psychological assessment in May, Mr Eaton said.
He said the charges against his client should have been dropped earlier.
"The media reports don't give you a sense of the turmoil that he's been through these last several months. To have your face recognised under this label - the face of looting - it's been a hellish time for him to have to endure."
Diversion dispute
Police today said Mr Smith-Voorkamp did not qualify for the diversion scheme, which would have allowed him to be discharged without conviction.
Mr Cliff said for police to grant diversion, an offender needed to be proved guilty and admit responsibility.
Mr Smith-Voorkamp could not be granted diversion as his mental impairment offered a justifiable defence to his charges, Mr Cliff said.
But Mr Eaton said that argument was "nonsense".
He said police refused to grant Mr Smith-Voorkamp diversion after he admitted the charges and pleaded guilty in March.
When that plea was changed to not guilty in July, police blamed the fact he could possibly defend the charges for not granting him diversion, Mr Eaton said.
"They clearly had come to the view they weren't going to grant diversion come hell or high water."
