At the Salem witch trials near the end of the 17th century, if the accused sank and drowned, they weren’t a witch, but if they floated, they were, in which case they were burned at the stake. Therefore, once the allegation was made, the accused was doomed. Last week, at the end of a phone hacking trial that cost all involved almost £100million,  Rebekah Brooks floated.

Not for nothing did her barrister, Jonathan Laidlaw QC, refer to the Salem witch trials during his summing up of the nine month trial in May. The reaction, particularly on social media,  to the pronouncement by the jury of “not guilty” on Brooks showed that Laidlaw had it right. It seems that in the case of Rebekah Brooks, many people who would should loudest about miscarriages of justice on anyone else were only prepared to accept one verdict.

The truth is that she simply wasn’t proven guilty. That is how the British justice system works, and I am glad about that. I personally would rather have some guilty people walking around free than have not guilty people in prison – it is a price worth paying in a liberal democracy.

At the end of the trial, Greg McGill, a senior Crown Prosecution Service (CPS) lawyer, blithely said that this “lengthy and complex trial was required to explore a culture of invading privacy”. Absolute rot. The CPS’s job is to prosecute and prove criminality – which involve literal, factually verifiable breaches of the law. We have pressure groups and a few politicians whose role it is to push idealistically for the betterment of society. It is not for the CPS to do. We had the Leveson inquiry, set up in 2011 by David Cameron, specifically to investigate the “culture, practices and ethics” of the press. That wasn’t a court of law – which is perhaps why so many self-interested celebrities and politicians were allowed to come in and tell us the tabloids were guilty without ever being cross-examined. In a liberal democracy the law must be steady, dispassionate, literal, far above opinion and prejudice.

Yet – and this for me is the most striking fact about this case that cost the taxpayer £30m – 200 police have been involved. That means that more detectives investigated who hacked Milly Dowler’s phone than had investigated and pursued her murderer.

So, what did they come up with on Brooks? Well, it was shown that Glenn Mulcaire, the private investigator whose notes are at the centre of this case, was given 5,600 tasks by the News of the World during the period under investigation. Of those 550 were during the time Brooks was editor. Laidlaw, her QC, was able to challenge all but 12 of these tasks as it was ambiguous whether the task was to hack or to blag confidential data. He also pointed out that the fact that Mulcaire had listened to voicemail messages 12 times when Brooks was editor did not mean that she knew about it.

The prosecution talked about the £92,000 a year contract with Mulcaire which they argued Brooks must have asked about before authorising it. But the role of Editor is not to micro-manage a budget, it is to give departments spending limits and ask questions only if they exceed them – which the news department didn’t. Also, Mulcaire’s company was paid weekly, so she may never have seen the £92,000 figure anywhere.

Talking of her being an Editor, it was asked why she wasn’t asking where stories come from. It was pointed out in court by a former editor that this didn’t reflect the reality of the modern newsroom. Journalists are ‘secretive; about their confidential sources, and stories were checked by department heads and the in-house legal team before being published. Brooks’ role was to oversee the whole process, not to ‘police’ the experienced journalists and news editors who worked under her.

Prosecution barristers made much of the hacking of Milly Dowler’s phone in 2002. Brooks was on holiday at the time, leaving Andy Coulson in charge. She had been in telephone contact with Coulson but she said they talked a lot more about a front page story about an Eastenders actor than about the Dowler story.

Brooks was also charged with bribing public officials. Brooks had been proven to have approved payments to a Ministry of Defence civil servant on 11 occasions. But the reporter involved had only called this civil servant his “number one military contact” – with no mention in the emails of her name or role. A busy editor dealing with an experienced supporter could not be expected to assume the payments were related to a corrupt official. There is no proof that Brooks ever asked who it was, no legal proof that she knew the cash was going to a civil servant.

The next accusation involved Brooks’ PA removing boxes of documents from the News International archives on the day the paper closed. But the PA said they were her documents she was taking home and hadn’t told Brooks she was even taking them. As we also know, there was film of the Brooks’ security staff and her husband Charlie Brooks hiding items from the police about to search their flat. Brooks had to admit it was his porn collection – he would probably have known that the existence of that would have been leaked to the press within minutes of the police finding it – and the prosecution couldn’t prove otherwise.

The point about all this is that not guilty verdicts can be given because the jury decides that the evidence presented to them does not meet the high standards required for a conviction. It DOESN’T necessarily mean they think the defendant definitely didn’t do the crime. Often, juries may think someone is guilty on the balance of probabilities but if they can’t be 100% sure that the defence’s explanation of events is impossible then they should not convict.

Nick Davies, who was the Guardian journalist who had pursued this case for over a decade, went on Newsnight on the night Brooks was found not guilty and admitted that having been in court every day it was obvious to him that the prosecution’s case against Brooks was not strong enough. There was no “smoking gun” (compared to Coulson – who had admitted listening to David Blunkett’s voicemails and who had actually written “do his phone” on an email instruction to a journalist). Davies accepted that the British legal system had run its course correctly and everyone else – whatever they think of Rupert Murdoch or Rebekah Brooks – should do that too.