Arthur Slugworth also known as Mr. Slugworth and later Mr. Wilkinson toward the end of the film is the main antagonist, later anti-hero in the Roald Dahl's children books, Charlie and the Chocolate Factory and Charlie and the Glass Elavator, and the movie adaptions of Charlie and the Chocolate Factory.
In the book, Arthur Slugworth is one of Willy Wonka's rival chocolatiers. Slugworth, along with Wonka's other rivals Mr. Fickelgruber and Mr. Prodnose, sent in spies to steal the secret recipes to Wonka's treats. Having obtained these, he began making candy balloons that a consumer blows up to incredible sizes, and then causes to burst before eating them; a plagiarized invention. The work of Slugworth (along with the other rivals) came close to ruining Wonka's factory. Wonka was forced to close his factory and fire all his workers. A few years later, Wonka's factory began working again (operated exclusively by Oompa-Loompas) and his work continued to dominate the candy industry, with no rival able to plagiarize his work because using the Oompa Loompa as his workers enables Wonka to operate his factory without regular employees and keeping it off-limits to the public, so no spies can infiltrate. Slugworth is never heard from again, but it is stated that Slugworth, Prodnose, or Fickelgruber would each give their front teeth to enter Wonka's inventing room (a laboratory) for five minutes.
In the 1971 film, Willy Wonka and the Chocolate Factory, Slugworth's company is in business. Inside Bill's Candy Shop, Wonka's products and signs are the most visible; but Slugworth's Sizzlers are also prominently displayed, and one is even sold to a child called June Marie. Also seen are signs for Fickelgruber's candy. Grandpa Joe describes Slugworth as the worst of Wonka's rivals, telling Charlie that he was one of those who sent his spies in dressed as Wonka workers to steal Wonka's Recipes.
A man calling himself Slugworth is a prominent character later in the film. As each Golden Ticket is found, a sinister man approaches the finder and whispers something into his or her ear. After Charlie finds the last ticket, the same man approaches Charlie as well, and delivers what is presumably the same speech he has given the other children. He introduces himself as Arthur Slugworth, president of Slugworth Chocolates Incorporated, and bribes the child to bring one piece of the newly invented Everlasting Gobstopperto him so he can discover and plagiarize the formula. Two of the children respond to Slugworth's bribe. Veruca Salt crosses her fingers behind her back when Willy Wonka asks the children to promise not to show the Everlasting Gobstopper to anyone else. Mike Teevee asks his mother what secrets they can sell to Slugworth; his mother is also heard telling her son to keep his eyes peeled and his mouth shut. Grandpa Joe also responds near the end of the movie. After Willy Wonka snaps at him and Charlie Bucket for stealing Fizzy Lifting Drinks, Joe threatens to give Slugworth the Everlasting Gobstopper. However, Charlie can't bring himself to betray Wonka and thus returns the Everlasting Gobstopper to Wonka.
Touched by this display of selflessness, Wonka forgives the theft of the Fizzy Lifting Drinks and reveals that the man isn't Slugworth, but a fellow Wonka worker named Mr. Wilkinson, and that his offer was a moral test of character.
The movie does not explain how the false Slugworth was able to approach each winner so soon after they found their tickets. However, it's implied Wonka somehow managed to keep track of each ticket's destination and then he told Wilkinson where they're most likely to be found.
Slugworth/Wilkinson was played by Gunter Meisner, a West German actor.
- Slugworth only makes a split-second appearance in Tim Burton's Charlie and the Chocolate Factory. He receives a secret recipe from Prodnose and is not heard of again.