THE man who first raised allegations of corruption which led to a major three year investigation into Cleveland Police said tonight it had been necessary.

However, retired head of crime operations, Mark Braithwaite, said he was "saddened and disappointed" to see the force's reputation so badly damaged by the Operation Sacristy findings.

"The force, the public, the service has been badly let down," he said. "The information that's recently been made available over the course of this last week has caused massive damage to public confidence."

In 2010, the then Detective Chief Superintendent received an allegation that Dave McLuckie, the former chairman of Cleveland Police Authority, had received a £50,000 'bung' from a local businessman in return for inside information - which later proved false.

Mr Braithwaite alerted Her Majesty's Inspectorate of Constabulary which inturn began a review into how some individuals within the force "may have conducted some of its business".

This led to Operation Sacristy, which itself cost £4.6m, into the spending culture of Cleveland Police - resulting in the sacking of Chief Constable Sean Price and his deputy, Derek Bonnard.

It concluded last week with the Crown Prosecution Service confirming there was insufficient evidence to bring criminal charges against nine people arrested as part of the inquiry.

These included Mr Price, the force's former solicitor Caroline Llewellyn and Mr McLuckie.

Mr McLuckie resigned from his post and was later jailed for perverting the course of justice after it emerged he persuaded a friend to accept speeding points on his behalf.

Operation Sacristy examined a complex set of allegations involving the misuse of corporate credit cards, expenses, hospitality and the issuing of contracts.

The inquiry revealed evidence of 'mismanagement, favouritism and an endemic culture of exploiting hospitality' - with thousands of pounds of public money spent on expenses for foreign trips, exclusive hotels and expensive restaurants together with the awarding of untendered police contracts.

Mr Price has described the probe as a witch-hunt and a waste of money while Mr McLuckie said the claims of 'serious corruption' were unjustified.

However, Mr Braithwaite said he had no regrets, adding: "It was entirely appropriate in my view that I raise it with the chief officer team and secondly with Her Majesty's Inspectorate.

"I felt there was a significant public interest in the matter that I'd raised and I felt that should receive consideration at a higher level - not withstanding that Mr Price was already aware. I felt I had a responsibility and a duty to escalate it.

"It's a matter of huge regret for me, for the service, a service I was proud to serve for 30 years that this investigation has been necessary.

I believe the investigation was necessary. People in public office have got significant responsibility, power and control and wherever there are criminal or misconduct allegations they should be properly investigated. Public confidence demands it."