The BBC has come in for stinging criticism at the Fraser Inquiry into the cost of the new Holyrood
Mr Campbell criticised the BBC's refusal to hand over the tapes
Counsel for the inquiry, John Campbell, said the BBC's refusal to hand over tapes of a documentary on the project "bore the hallmark of arrogance".
The inquiry is hearing closing statements from lawyers after 43 days
Lord Fraser of Carmyllie is expected to deliver his report in September.
Mr Campbell said the BBC "has inexplicably failed to recognise where the public interest lies and by its refusal has in part thwarted the purpose of the inquiry".
He added that the corporation had subordinated the public interest to its own considerations.
"It seems to have forgotten that the agreement to film in the first place was with the former Scottish Office, and subsequently with the Scottish Parliament.
"It seems to have forgotten that the subject of the filming is a public project of the highest importance," the QC said.
The BBC has consistently refused to hand over interviews with the late Secretary of State, Donald Dewar and the architect Enric Miralles, who died in 2000, for a documentary entitled The Gathering Place.
Inquiry team members were allowed to see interviews with the two men, carried out for BBC Scotland by independent production company Wark Clements, on Monday but Mr Campbell argued that this was not enough.
In a submission to the inquiry, BBC Scotland lawyer Alistair Bonnington said it was "well known" that the corporation does not normally release untransmitted material, unless required to do so because of a court order
He said this was in accordance with BBC Producer Guidelines which state that it would "not voluntarily allow access" where this would make it difficult to gather such material in the future.
Mr Bonnington said this was a key issue in this case as to have handed over the material would have broken promises given to some interviewees about how the material would be used.
"Any media organisation which gives promises in order that it can obtain information and then breaks these promises when this is convenient will quite rightly have trust in their integrity seriously eroded," Mr Bonnington said.
Mr Campbell attacked early estimates of the project's cost. The QC told the inquiry that in 1999 civil servants were urging Mr Dewar to take the line that it was £50m.
Mr Campbell told Lord Fraser: "One of the issues to which you will have to give close consideration is whether the project ever had an adequate budget and any real semblance of cost control during this period.
"Or whether, in reality, this was a time when the seeds of many of the subsequent problems were being sown."
Civil servants are also expected to be among those criticised. Laura Dunlop QC will set out the Scottish Executive's case on Tuesday.
MSPs have been told the cost of the new parliament building remains unchanged at £431m.
Presiding Officer George Reid said that claims reported in Building magazine that the cost was set to go up by an additional £19m had "no basis whatsoever".