Silent Night, Deadly Night (1984) (UK-import)
American seasonal slasher horror. After years of abuse from the cruel nuns who ran the orphanage where he spent his childhood following the brutal murder of his parents, the now-teenage Billy (Robert Brian Wilson) gets a job at a department store. When he is asked to dress up as Santa Claus at Christmas time, traumatic memories are triggered in his mind and he loses the plot, embarking on a bloodthirsty rampage and killing everyone who crosses his path.