Which stormtrooper bonked his head on a door? Investigating a Star Wars mystery

More than 40 years ago, Star Wars was released with a surprising, if not iconic, moment — a clumsy stormtrooper striking his head on a door frame. 

Now, one British YouTuber believes he's tracked down the actor underneath the white armour, despite claims from two other actors that they are, in fact, responsible for what he calls the film's most "concussive blooper."

"When I first attempted to discover the mystery trooper, I was looking for someone and I went to Google, as you do," filmmaker Jamie Stangroom told Day 6 host Brent Bambury. 

"Google provided me with someones, because there are multiple actors basically claiming that they're that trooper." 

The results of Stangroom's investigation are revealed in a new online documentary, The Empire Strikes Door (A Star Wars Mystery).

The head bump is a moment many viewers will miss if they blink, but for Star Wars fans, it's well-known. In the scene, a group of stormtroopers are chasing the film's heroes through the Death Star. As a door lifts open, one stormtrooper's helmet collides with the opening door, momentarily setting them aback.

According to Stangroom, producer Gary Kurtz used the clip because it was the best take they had. Though it flew under the radar for years, a sound effect was added to the scene, highlighting the mishap in a 2004 DVD re-release.

Over three years, Stangroom investigated three actors — suspects, as he calls them — each claiming that they were the man underneath the clumsy stormtrooper's helmet.

The most famous of the bunch, late British soap star Michael Leader, declined to be part of the project. Two others, Laurie Goode and Martyn Reid, underwent a polygraph test to determine whether they truly believed they were the mystery actor.

Both actors are vehement it was them behind the mask. Goode even attends Star Wars fan conventions, offering autographs, as "the clumsy stormtrooper."

Despite that, the test came out in favour of Reid. Stangroom says telling Goode he failed was a "horrible moment."

"I genuinely believe that he believes he was that stormtrooper even though maybe he wasn't. So telling him that he's, perhaps, been living a lie for all of these years was horrible," Stangroom said.

Stangroom concedes, however, that not even director George Lucas could provide confirmation.

But in The Empire Strikes Door, Stangroom comes as close as he can to settling the matter by convening a panel of pop-culture experts, including filmmaker Kevin Smith and wrestler Chris Jericho.

The panel agreed: All evidence points to Reid.

While Stangroom agrees with the jury's conclusion, he still has doubts given his own experience wearing the stormtrooper suit.

"They really are, especially when you're moving, quite hard to see through," Stangroom said.

"So I'm convinced that they all bumped their head. And I'm convinced that they're all convinced that they did it in that scene."