washington britain top internal security official press social media company devise automatic systems spot block violent militant message post network amber rudd home secretary conservative british government lead prime minister theresa may tell audience new america washington think tank thursday night online arm race militants force law order rudd say government authorities company already work ensure militant message promote violence remove internet within one two hours initial post say company press ahead development deployment artificial intelligence systems could spot content post internet block disseminate since begin 2017 violent militant operatives create 40,000 new internet destinations rudd say note visit silicon valley company include alphabet inc google youtube facebook inc twitter inc early year call take block militant content 12 months ago social media company take half violent militant material sit within two hours discovery lately proportion increase two thirds say youtube take 83 percent violent militant videos discover rudd say add uk authorities evidence islamic state militant group struggle get materials online say much company use cut edge technology spot dangerous content quickly add wake increase number vehicle attack militants one london borough market early year british security authorities review rental car regulations consider ways authorities collect relevant data car hire company british official urge social media company block militant content