In the Star Wars universe, Stormtroopers are the armour-clad foot soldiers of the Empire - hundreds (perhaps thousands) can be seen in the films, gamely battling the Rebellion. But how many Stormtrooper toys exist in our world? Are they the biggest secret army on Earth?
This question is more difficult to answer than you might think. I had a bad feeling about the chances of success, but as Yoda would put it: "Do. Or do not. There is no try."
The toys based on the original films were made under licence by the US firm, Kenner, between 1978 and 1985. Kenner was absorbed into Hasbro in the 1990s. Now the toys are made by Disney. But none of these companies could give me sales figures for the number of Star Wars toys sold.
So, as Star Wars figures are popular with collectors, I asked several online communities if they had any idea how many there were. No-one had a number, but everyone agreed it was probably very big. One enthusiast claimed to have more than 200 Stormtroopers in his personal collection.
My first significant breakthrough came from an unlikely source - the Leicestershire County Council Museum Service. The original Star Wars toys were produced under license in the UK by a company called Palitoy. They had a factory in Coalville in Leicestershire, and the museum inherited some of its paper. An internal company newsletter from 1985 revealed it had sold 25 million action figures in the UK alone - more than one toy for every child in the country at the time.
Palitoy was famous for making a piece of Star Wars merchandise that has now become one of the most expensive to buy - a cardboard Death Star. Its designer, Bob Brechin, says Palitoy made its own model because the Kenner plastic model wasn't going to be ready for sale at Christmas 1978.
"It was basically two floors with about 10 rooms in it, with a little piece on the top with a gun emplacement - basically half a Death Star - so it was like a dome.
"And of course, being in card it got damaged, so they are very rare. So if you get a really pristine Death Star in the box, it's worth a lot of money… I wish I had kept a few."
Specialist auction house Vectis has sold one of these Death Stars for almost £5,000 ($7,500).
I wondered whether Vectis might have any idea how many Stormtroopers there are in the world. But sadly, they didn't.
I was not having much luck, but as Obi-Wan Kenobi, puts it, "In my experience there is no such thing as luck." So I persisted, and my next call - to Chris Taylor, author of How Star Wars Conquered the Universe - was very productive.
"One figure we do know is that a total of 300 million Star Wars figures - that's across all varieties - were sold by 1985," he told me.
"So already by 1985, you have more Star Wars figures in general in the world than Americans."
From this I estimate there were about 10 million Stormtroopers by 1985.
But that was 30 years ago. What has happened since?
In 1999 Lego started making Star Wars toys. It was, as Ahsoka Tano would have said, "a new day, a new beginning".
These toys have been a big success, spawning their own spin-offs, including computer games and books. And Lego was able to tell me how many Stormtrooper mini-figures it has sold.
That's a massive army. The International Institute for Strategic Studies estimates there are just under 20 million military personnel on Earth today. So Lego Stormtroopers alone outnumber every army on Earth by about 50-to-1.
So if there were a battle between Stormtroopers and humans, it would surely be a massacre.
Or maybe not.
Chris Taylor points out that the Stormtroopers' armour, apart from being the wrong colour from the point of view of camouflage, seems remarkably ineffective - just one shot hitting a Stormtrooper in the arm or the chest sometimes appears to be enough to put it out of action.
Fans have also developed theories to explain why their shooting is so inaccurate. Taylor's own theory - having tried on a helmet - is that their field of vision is very limited.
But there is another point too.
"I think the human race could win, because Stormtroopers were originally designed by George Lucas to represent the US military in Vietnam," says Taylor.
"So the whole idea was always that the Empire would lose to a lower level of technology.
"The [North Vietnamese] Vietcong in effect became ewoks at the end of the Return of the Jedi and that is the whole lesson of Star Wars - that you could win even if your numbers are small."
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