“The Inbetweeners Movie” is set to become one of the year’s biggest British hits after grossing an enormous £2.58 million ($4.26 million) on its first day of previews.The pic, distributed by Entertainment Film Distributors, opened Wednesday at 409 sites, and is on course to top $15 million by the end of the weekend. By comparison, “The King’s Speech,” the top British indie film of 2011 so far, took $5.5 million in its first weekend, while the 2010 champ “Streetdance 3D” took $3.6 million. The $5.8 million Film4 production is a spinoff from Channel 4′s cult sitcom about the misadventures of four teenage boys. The BAFTA-winning TV series ran for three seasons and ended when they left high school. In the movie, the quartet head off for a Greek holiday to celebrate their graduation. Pic stars Simon Bird, Joe Thomas, James Buckley and Blake Harrison, and was directed by Ben Palmer from a script by series creators Damon Beesley and Iain Morris. Producer is Chris Young. Entertainment Film Distributors has U.K. theatrical rights only. Channel 4 owns DVD and TV rights. IM Global racked up strong foreign sales at Cannes.