A £4.6 million investigation into alleged corruption and misconduct by senior police officers has ended with no-one facing criminal charges, the Crown Prosecution Service has said.
Those behind Operation Sacristy, the 41-month investigation into wrong-doing at Cleveland Police, said it was justified because it led to the dismissal of the Chief Constable Sean Price and his deputy Derek Bonnard.
The ex-chairman of Cleveland Police Authority Dave McLuckie resigned from his post and was subsequently jailed for perverting the course of justice after it came to light he persuaded a friend to accept speeding points for him.
The inquiry looked at a complex set of allegations of misuse of corporate credit cards, expenses, hospitality and favours.
Mr Price said it was a "disgrace" he had been on bail for two-and-a-half years.
He became the first chief constable for 35 years to be sacked after he was found guilty at a disciplinary hearing of gross misconduct.
He said: "My extremely high profile arrest ruined my life and my reputation, and it is now clear for all to see that it was completely unnecessary, disproportionate and unlawful.
"The ongoing and misguided criminal investigation has been a complete waste of £5 million of public money".
That view was rejected by Keith Bristow, director general of the National Crime Agency, who was asked to lead the inquiry while he was chief of Warwickshire Police.
Speaking at a news conference at the force's headquarters in Middlesbrough, he said: "As a result of our investigation and an independent investigation by the Independent Police Complaints Commission, a number of people have been removed from public office.
"The former Chief Constable and Deputy Chief Constable were both dismissed without notice for gross misconduct.
"The former Chair of the Police Authority resigned and was subsequently convicted of perverting the course of justice.
"Several other people who were subject of investigation and also held senior public positions have left their jobs with Cleveland Police and the former Police Authority."
Usually, disciplinary hearings follow criminal proceedings, but that was reversed in this case, he said.
That saved the public purse, as senior figures were taken off the pay-roll months before the CPS made a decision to prosecute, he added.
"It also enabled new leaders to be appointed to enable Cleveland Police to implement necessary changes in policy, practice and governance and drive the force forward," he said.
Operation Sacristy found there was a lack of ethical leadership at the force and police authority, and "a multi-lateral breakdown of standards, poor practices and breaches of regulations, policies and procedures".
Mr Bristow said: "Sacristy also found evidence of mismanagement, favouritism and an endemic culture of exploiting hospitality.
"Some very senior individuals in key posts failed in their responsibility to act in an honest and open manner and there was a breakdown of any effective checks and balances.
"Standards of conduct were incompatible with expectations of senior public servants."
Mr Price's replacement as chief constable Jacqui Cheer said: "The individuals investigated during the course of this enquiry have behaved unethically and inappropriately.
"They have let themselves down, they have let their colleagues down, and most importantly they have let down the public they vowed to protect and serve."
But there was not enough evidence to warrant prosecution.
Alison Saunders, Director of Public Prosecutions, said: "A realistic prospect of conviction means that a conviction is more likely than not.
"In considering whether there is sufficient evidence to prosecute, the test makes it plain that it is not just the prosecution evidence or approach which should be considered, but also the likely defence case, and prosecutors must consider all the evidence carefully.
"As a matter of law, a prosecution for corruption, fraud or for the criminal offence of misconduct in public office requires more than, for example, poor administration, maladministration or breaches of rules and procedures.
"Having thoroughly reviewed the reports and evidence, we have determined that, whatever criticisms may be made about the conduct of the various suspects, including any police discipline findings, the available evidence does not give rise to a realistic prospect of conviction in connection with conduct relating to the administration of Cleveland Police and Cleveland Police Authority.
"There can therefore be no prosecution of the individuals considered."
Barry Coppinger, Cleveland PCC (Police and Crime Commissioner), said it was now time "to put the past behind us".
He said: "Cleveland Police is a well-run, well-governed organisation that has made changes over the last two years which include reducing the number of corporate credit cards, updating policies on gifts, hospitality and corporate credit cards and introducing an Integrity and Transparency Board."
Mr McLuckie said his life has been ruined by the investigation "which should never have happened".
He said: "It is now clear that the claims of 'serious corruption' were never justified and those who repeatedly made those statements in an attempt to justify Sacristy should be called to account.
"Of course, there will be many who will try to now close the door and say that we should all 'move on' but that cannot happen unless those who have caused so much damage and incurred so much cost are properly answerable for their actions."
The Home Office has covered the £4.6 million cost of Operation Sacristy.
The investigation cost £3.9 million and the misconduct hearings a further £700,000.
A civil claim against Mr Price to recover money he was paid above his statutory salary is under way.
James Wharton, Tory MP for Stockton South, said the force was not out of the woods yet.
"There are serious outstanding questions about the scale and cost of Sacristy given that no charges are being brought against Sean Price," he said.
"He has lost his job, been subject to very difficult public examination and debate and must be relieved to not now face prosecution, if this was ultimately nothing more than a misconduct investigation into him then the cost and scale are very difficult to justify.
"We are a long way from re-establishing public trust in the way Cleveland Police is run, with a whole host of issues having come up through and since this investigation.
"It is clear there is some way to go and local MPs and the Police Commissioner need to do more to hold decision-makers to account than has been the case in the past.
"Cleveland Police is not out of the woods yet."