The City of London Police has defended the race-fixing investigation which ended with the collapse of a £10m trial but said procedures could be tightened.
Ex-champion jockey Kieren Fallon and five others were acquitted in December.
But Mr Fallon's solicitor dismissed the police's internal review and said he had asked the attorney general for a full inquiry into the fiasco.
On Thursday a review by the British Horseracing Authority (BHA) decided it
had acted by the book.
Mr Fallon, jockeys Fergal Lynch and Darren Williams, businessman Miles Rodgers and two other men were acquitted of conspiracy to defraud after the judge ruled there was no case to answer.
I am pleased to say that we got a lot of things right, including the overall direction and control of the investigation
Commander Patrick Rice
Mr Justice Forbes said the prosecution case had failed largely because the star witness, Australian racing expert Ray Murrihy, was not an expert on British racing and his evidence had been completely undermined in cross examination.
The prosecution had also played down the evidence of British racing expert Jim McGrath, who said he saw nothing wrong in any of the jockeys' riding. His comments were only disclosed at the last minute to the defence.
THE ACQUITTED MEN
Kieren Fallon, 43, from Tipperary, Republic of Ireland
Fergal Lynch, 29, from Boroughbridge, N Yorkshire
Darren Williams, 29, from Leyburn, N Yorkshire
Shaun Lynch, 37, from Londonderry, N Ireland
Miles Rodgers, 38, from Silkstone, S Yorkshire
Philip Sherkle, 42, from Tamworth, Staffs
Defence lawyers also highlighted the conduct of the investigating officer, Acting Detective Inspector Mark Manning, who went for a job at the BHA before the trial.
It was also revealed that the police had asked the BHA to pay £411,000 towards the cost of the investigation, which they declined.
Cdr Patrick Rice, who led the City of London Police's review, said: "This report is the result of several months of painstaking work by the review team.
"I am pleased to say that we got a lot of things right, including the overall direction and control of the investigation. However, we have also identified some areas where we need to tighten up our processes and modify our ways of working."
The Operation Krypton team conducted more than 500 interviews, obtained 1,300 statements, collected 17,000 exhibits and produced 40,000 pages of evidence.
The review pointed out the decision to charge was made by the Crown Prosecution Service, having seen all the evidence.
The report said: "During the trial defence counsel made a number of suggestions that police officers acted improperly and sought to withhold evidence from the court.
It's very difficult to treat the City of London Police's internal review at all seriously
Ian Burton Kieren Fallon's solicitor
"The review has found no evidence to suggest any improper conduct or deceit by any of the officers linked to this investigation. Officers involved were dedicated and professional throughout a complex, challenging enquiry, in what was unchartered territory for police investigations."
But it did make several recommendations, including:
• The procedures in place for disclosure should be reviewed. Every effort must be made to avoid any suggestions of withholding evidence from the court.
• The force should adopt national guidelines on the identification and appointment of expert witnesses.
• The force should draw up a written protocol when working with regulatory bodies like the BHA.
• The force should introduce a formal policy about how such inquiries should be funded.
• Discussions and decisions on police officers presence at court during trials are formally recorded.
But Mr Fallon's solicitor, Ian Burton, told the BBC News website: "It's very difficult to treat the City of London Police's internal review at all seriously because on the day the trial collapsed Commander Rice went on television and said that it was a great shame that the judge had not let the trial continue so the jury could hear all the evidence.
Commander Patrick Rice defends the inquiry
"But the fact was that the trial judge - the second most senior high court judge in the country - had seen ALL the evidence and had concluded there was no evidence of a conspiracy. I don't see the purpose of an internal review."
He said they had referred a full dossier to the Attorney General, Baroness Scotland, and it would be months before her enquiries would be completed.
City of London Police is currently conducting an investigation into alleged corruption in football.
Portsmouth manager Harry Redknapp has taken the force to court over his arrest, which involved a dawn raid at his home in Dorset. The police were accompanied by press photographers but they have denied leaking the raid to the press.
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