South Yorkshire Police had no legal duty to tell the whole truth "warts and all" when providing officer statements to an inquiry into Hillsborough, a court heard.
Sir Robert Francis, QC, said he believed there was no professional obligation for the force to be "candid".
He added an authority could choose what information to give to a public inquiry and what to leave out – so long as it did not mislead proceedings.
His opinions came as he gave evidence at the trial of two former South Yorkshire Police officers and a solicitor who worked with the organisation in the aftermath of the 1989 tragedy.
Ex-Chief Superintendent Donald Denton, former Detective Chief Inspector Alan Foster and Peter Metcalf each deny two counts of perverting the course of justice.
Prosecutors have accused them of amending dozens of officer witness accounts to "mask the failings" of South Yorkshire Police at the FA Cup semi-final between Liverpoool and Nottingham Forest in Sheffield.
The accounts were being collected by West Midlands Police ahead of the Taylor Inquiry into the tragedy, which unfolded at the Leppings Lane end allocated to Liverpool supporters. Ninety six men, women and children died as a result.
Sir Robert, called as an expert witness by Metcalf's defence team, gave evidence to the trial on Tuesday.
Jonathan Goldberg, QC, defending Metcalf, asked whether the witness believed there was, in 1989, a "duty of candour incumbent upon a chief constable" when providing voluntary written recollections to a non-statutory public inquiry?
Sir Robert, who has chaired a number of public inquiries, responded: "I understand you are talking about a legal duty of candour and there was none."
He added: "I don't recall there being any professional duty on someone like a chief constable or the chief executive of an NHS Trust to be candid in the sense of producing everything warts and all."
The witness said he believed there was no such duty on individual officers or a lawyer advising them.
Sir Robert said that, generally a lawyer's duty was to do their best for their client "in accordance with the law".
He said, however, they did have a duty "not to mislead".
Sarah Whitehouse, QC, prosecuting, asked him whether he was suggesting it was "perfectly alright" for a public body to suppress information at a public inquiry.
Sir Robert said: "I haven't said it is perfectly alright. It is not unlawful to choose what to volunteer to the inquiry as long as it is not misleading."
Later asked by Mr Goldberg what it meant to a lawyer to mislead by leaving a topic out of a witness statement, he said "if what remains gives an impression that is misleading, then it is misleading."
Denton, 83, Foster, 74, and Metcalf, 71 each deny doing acts tending and intended to pervert the course of public justice.
Their trial, presided over by judge Mr Justice William Davis, follows an investigation by the Independent Office for Police Conduct and is scheduled to last up to 16 weeks.
It is being held in a converted court at the Lowry theatre in Salford.