In an early scene, Scrooge refuses Samuel Wilkins' request for a Christmas postponement, by saying "You'd still owe me £20 you're not in a position to repay if it was the middle of a heatwave on an August Bank Holiday". This refers to a law enacted in 1871, after Charles Dickens' death.
When Scrooge gives his housekeeper a Christmas Bonus and
increases her wages to ten shillings a week, she runs down the stairs exclaiming in joy "Bob's your uncle!" This phrase commemorates British Prime Minister Robert Cecil's appointment of his unqualified nephew, Arthur Balfour, as the Chief Secretary of Ireland, in 1887, 17 years after Charles Dickens had died.
From, the ledger dates and costumes etc., it is clear that the film is set in the 1840s. On a wall in the home of Scrooge's nephew, Fred, however, hangs a print of "Monarch Of The Glen," an 1851 painting.
Mr. Jorkin quotes the line "Curfew shall not ring tonight" as if it is a well-known phrase. Although Rose Hartwick Thorpe wrote the poem "Curfew must not ring tonight" in 1867, the line (a misquote of the title) did not become popular until around 1900.
A group of coal miners perform "Hark the Herald Angels Sing" in the 1840s. The particular version they're singing wasn't arranged until 1855, when musician William H. Cummings synchronised John Wesley's 1739 verse to the tune of Felix Mendelssohn-Bartholdy's 1840 Gutenberg Cantata.
When Peter Cratchit is reading from the Bible, after the camera pans away from him, the voice clearly changes to someone else's. Shortly before the camera pans back to him, the voice changes back to the actor's.
When Scrooge walks into the room of his house and first meets the Ghost of Christmas Present, loud and boisterous laughter can be heard coming from the spirit. This is the kind of laughter that requires someone's mouth to be wide open, yet the spirit's mouth is mostly closed, with a toothy grin.
Early in the movie, Scrooge is complaining about having to give Bob Cratchit Christmas day off with pay. Scrooge puts his scarf on and then Cratchit helps him put his coat on, over the scarf. In the next shot, Scrooge is seen walking outside with the scarf wrapped over his mouth, outside of his of coat.
In the final scene, a blind man stands with his dog outside an alley which has Greek columns and a flat entrance ceiling. Someone inside the alley would see the man and the dog. However, when Scrooge is inside the alley and the camera is looking back, the blind man and the dog have disappeared and the alley now has an arched entrance with a lantern attached.
The final scene with Scrooge about to enter an arched alleyway, he turns upon hearing Tiny Tim call out. The camera switches to a view from inside the alleyway to facing Tim: it's painfully obvious this is not the same alley. It is easily twice the size of the first with a much higher arch. And now, Scrooge is suddenly so deep into the alley that he's out of camera range.
The first time the outside door to Scrooge's office is opened, there is no lettering visible on the exterior side of the door's glass. But "Scrooge and Marley", reversed, is clearly visible from on the interior side. In later scenes, the outside window is lettered.
The opening titles begin with a hand taking a copy of the book "A Christmas Carol" from a shelf of several of Charles Dickens' works (including two copies of "David Copperfield" and "A Christmas Carol"). All the copies are the same size. In reality "A Christmas Carol" is a comparatively short work and would be a much thinner tome than the others depicted on the shelf.
Alice seems to age very little between the past and present scenes, compared to Scrooge. This could be to show the contrast between the two - she chose to stay on the "good" path and has a healthier spiritual condition, he turned to greed and anger and has prematurely aged.
From the day he buys Mr. Fezziwig's shop (which employs a very young Scrooge and Marley) until his retirement with embezzled funds (when those two are much older), Mr. Jorkin doesn't seem to age a day.
When Scrooge calls to the boy in the street to buy the turkey, he leans on the ledge of the window as viewed from the outside. From inside, however, the ledge is seen to be not more than a foot or two up from the floor.
When Scrooge enters his residence on Christmas Eve, he locks the door and then reaches up and slides a dead bolt so that the door cannot be opened from the outside. The next day, Christmas morning, the housekeeper enters his room while he is still in bed.