Bill Nighy once famously complained of being the only English actor who hadn't been cast in a 'Harry Potter' film. Luckily for him (and us!), he was offered the role of Minister of Magic Rufus Scrimgeour shortly after.

Though it certainly seems like every high-profile British actor from Emma Thompson to Helena Bonham Carter to Alan Rickman to Gary Oldman has appeared in the franchise at some point, there are still a significant number of seasoned Brits who haven't dabbled in the 'Harry Potter' magic. (Vanity Fair even compiled a list of 76 venerable British stars missing from the films.)

Some absences are less mysterious than others. While most thespians would kill for a spot in the films, others have said they wouldn't be caught dead in the wizarding world of 'Harry Potter.' Most notably, Tilda Swinton has publicly declared her distaste for the 'Harry Potter' films, reportedly complaining that the franchise "fetishizes boarding school for children." (Sounds like someone didn't have fun rubbing elbows with Princess Diana at the West Heath Girls' School.) Of course, most stars would not echo Swinton's sentiments. As Nighy once told Premiere magazine, "'Harry Potter' is an institution in England. It has become a national cultural treasure."
As many were clamoring for a spot in the films, others were trying to sort out scheduling conflicts. Case in point: Hugh Grant was apparently set to play Gilderoy Lockhart (which ultimately went to Kenneth Branagh), but had to back out due to other obligations -- it's still unknown whether he has any regrets.

We probably wouldn't change a thing about the existing 'Harry Potter' movies. They were beautifully crafted and incredibly well-acted. That said, it's always fun to play the "what if" game, isn't it? Especially on the day before the release of 'Harry Potter and the Deathly Hallows, Part 2.' So in that spirit, what if these five (10, if you count the hypothetical understudies) British acting legends were cast in some of the saga's most memorable roles?

Jeremy Irons would have been perfect as Professor Snape. In fact, we get a glimpse of what could have been in the Comic Relief 'Harry Potter' parody below, where Irons spoofs Snape. Irons was reportedly in talks to appear in one of the films, but he wouldn't reveal any specifics. What a tease!

Understudy: Tim Roth, who apparently read for the role.

Kate Winslet would have made a fascinating Bellatrix Lestrange. It was rumored that she was set to play French hottie Fleur Delacour in 'Goblet of Fire,' but scheduling conflicts may have kept that from coming to fruition. Winslet is good in whatever she tackles, which is why we really would have liked to see her unique spin on the eeeevil Bellatrix.

Understudy: Kristen Scott Thomas. Wouldn't it be great for her to let loose after playing so many tightly-wound English ladies?

Ian McShane would have nailed the role of Sirius Black. Sirius is hardened and world-weary, not unlike McShane's iconic character Al Swearengen on 'Deadwood.' Plus McShane is kind of a badass, so we could definitely see him sparring with his evil cousin Bellatrix.

Understudy: Christian Bale. Though, upon further consideration, he probably shouldn't be working with so many children given his penchant for on-set outbursts.

Daniel Day-Lewis would have been great as Lucius Malfoy. He's already got the 'horrible father' character down pat (ahem, 'There Will Be Blood'). And yes, we would have loved to see him with long, blond hair.

Understudy: Paul Bettany. He has that creepy albino look going for him.

Judi Dench would have been perfect as the 'evil in pink' Dolores Umbridge. It would have been fun to see Dench taking orders from her evil overlords as Umbridge, after seeing her play the boss so often as M in the 'James Bond' flicks.

Understudy: Helen Mirren. She demonstrated her aptitude for playing an evil teacher in 'Teaching Mrs. Tingle.'

(Photos supplied by Getty Images)
Harry Potter and the Deathly Hallows: Part II
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As his showdown with Lord Voldemort nears, Harry may have to make the ultimate sacrifice. Read More