Scholarship, my advisor in graduate school always reminded us, is a wall you build brick by solitary brick. You add your bricks to those assembled before you and hope the subject is important enough that the next scholar to come along will raise the edifice a little higher than you managed.

Documentary films aren’t usually assembled the same way or looked at as primary scholarship. But the movie “Coup 53,” about the MI-6 and CIA-sponsored Iranian coup of 1953, brings to light startling evidence of Britain’s primary role in the planning of it, something the United Kingdom has been united in denying for nearly 70 years.

As seen in the film, this coup — which eventually saw the Shah of Iran installed as supreme leader with dictatorial powers — was a desperate move engineered by a crumbling British empire clinging to oil fields and a showpiece refinery lost when a democratically elected Iranian government nationalized them.

After a somewhat self-promoting opening that includes a sample of his TED talk about this subject and revealing his personal connections to the story, director Taghi Amirani paints a brief, worshipful picture of Mohammad Mosaddegh, the prime minister who insisted that Iran’s resources were Iran’s to exploit, and no longer the property of the British.

“He was the closest Iran came to have its own Mahatma Gandhi!”

A privileged, well-educated member of the lesser nobility, others in the film describe Mosaddegh as “eccentric” (He was as fond of pajamas, and bedside meetings, as Hugh Hefner.), both a social democrat and a “a feudal warlord” who tolerated Iran’s communists only because they were the only organized political party in the peculiar “Persian Empire” vestiges of a British protectorate.

And in 1953, Churchill and his Conservative government, with a little urging from the company that would change its name to British Petroleum after the coup, plotted with the Shah to depose Mosaddegh in an event still recalled with vehement bitterness in Iran.

Making what is largely a documentary about making a documentary, filmmakers Amirani and editor and co-writer Walter Murch use Ali Charmi’s striking animation to recreate the coup itself, and events leading up to it. And they do a splendid job of showing us lots of “bricks” pulled together by others who came before them in building the most complete account of this coup, how it happened and who planned it, and its implications for the history of the Middle East.

The Iranian born and British educated Amirani spent nearly 10 years working on “Coup 53.” As the film shows, there is a whole subculture of Iranian expats who have kept the memory of this outrage alive, preserving archives, newspaper accounts, interviewing on camera survivors, combatants and plotters. Their exhaustive work is generously offered and generously added to the wall Amirani and Murch are building.

Several historians who have written books on the coup and this fateful moment in Middle East/Western relations appear and ponder the “What ifs” of a “regime change” — plotted by Allen Dulles of the CIA, with Eisenhower’s approval, and Churchill’s MI6 — the ways it altered the history of the region forever and shaped American ideas of how “easy” regime change could be.

Most importantly for the makers of “Coup 53” was the research done for a British documentary TV series in the ’80s that interviewed most of the surviving British protagonists about this “chapter” in British history. “End of Empire” (1985) adds significantly to the “meat” of Amirani and Murch’s new film, which samples interviews from many of those involved who have since died.

And then there’s that fellow who didn’t appear on camera, not that ITV/Granada Television will admit, anyway. Norman Darbyshire was a British intelligence officer, not quite 30 years old when he “arranged” the coup. In 1985, Darbyshire wasn’t shy about speaking his mind and spilling the beans, no matter what denials his government continued and continues to make about the 1953 coup.

The “twist” that Amirani makes the most of here is the fact that no video or audio of Darbyshire’s keystone interview exists. There’s just a transcript.

A lot of “Coup 53” is spent showing us the efforts the filmmakers went to in trying to confirm this happened. When they’re satisfied they have, they convince actor Ralph Fiennes — perfect, of course — to “play” Darbyshire in a recreation of this interview, cynically talking about British racism, callous high-handedness and the many ways Pounds Sterling greased the wheels for removing a popularly elected leader from a budding democracy because it was bad for (future) BP.

The sea of talking heads appearing here tend to dull the senses in between flashes of animated action and a Darbyshire interview made as le Carré chilling, officious and suspenseful as Fiennes could manage. After a brisk opening act, the film tends to bog down until we get to the third act’s bloody nitty gritty of the coup. “Coup 53” could stand to shed some minutes.

Some of the claims of “censorship” and have been disavowed by the original production company, some of the “revelations” debunked, with Amirani criticized for sensationalizing the way the transcript of an interview not used in “End of Empire” was “leaked” to journalists and then to Amirani. I’m willing to buy into his claims of “censorship,” but others got hold of his “big revelation,” which was publicized 35 years ago, even if he didn’t know it.

The film was yanked from distribution for a bit over clearance rights (money) to those archived ITV interviews.

“Coup 53” is still a lively treatment of important history, adding bricks to the wall of what scholars know about Iran, Britain and the U.S. (with Israeli involvement, training the Shah’s dreaded secret police) at that time, what happened and how. Now it’s up to other scholars to take up the story and make their additions to it.

MPA Rating: unrated, depictions of violence

Cast: Taghi Amirani, Malcolm Byrne, Alison Rooper, and Ralph Fiennes.

Credits: Directed by Taghi Amirani, script by Taghi Amirani and Walter Murch. An Amirani Media release.

Running time: 1:59