The Daleks have exterminated their rivals as Doctor Who's scariest villains despite the creation of new hi-tech enemies, according to a new survey. The Daleks, which were almost left out of the BBC's modern Doctor Who, have seen off threats by new monsters such as the Beast and the Empty Child Zombies. A poll of 21,000 Doctor Who fans was commissioned to mark the Daleks' debut appearance in the third series of the revived BBC show on Saturday night. Nick Briggs, the voice behind the Daleks, said: "I've been fortunate enough to provide the voices for a wide variety of Doctor Who villains over the years, but the Daleks seem to have stood the test of time as the scariest and most iconic space terrors that the Doctor has ever encountered." Doctor Who senior script writer Russell T Davies said: "Every time the Daleks return we make them bigger and better than ever before, and this time, their plan is the most audacious Dalek scheme yet." He warned: "Even the Doctor finds himself out of his depth." The Daleks feature in a special two-part story, featuring David Tennant and new companion Freema Agyeman, set in 1930s New York. Doctor Who fans were horrified when the Daleks were originally ruled out of the comeback show after the BBC and creator Terry Nation's representatives failed to agree a deal - but they were eventually reinstated.