os ▁K ou mart z is , ▁an ▁MA ▁research er ▁at ▁London ▁College ▁of ▁Communic ation , ▁the ▁vast ▁majority ▁of ▁UK ▁based ▁Internet ▁users ▁( 9 0 . 2 1 %) ▁were ▁una ware ▁of ▁the ▁existence ▁of ▁C lean feed ▁software . ▁Moreover , ▁nearly ▁two ▁third s ▁of ▁the ▁participants ▁did ▁not ▁trust ▁British ▁Tele communic ations ▁or ▁the ▁I WF ▁to ▁be ▁responsible ▁for ▁a ▁silent ▁c ensor ship ▁system ▁in ▁the ▁UK . ▁A ▁majority ▁would ▁prefer ▁to ▁see ▁a ▁message ▁stating ▁that ▁a ▁given ▁site ▁was ▁blocked ▁and ▁to ▁have ▁access ▁to ▁a ▁form ▁for ▁un block ing ▁a ▁given ▁site . ▁ ▁C lean feed ▁originally ▁target ed ▁only ▁alleg ed ▁child ▁sexual ▁ab use ▁content ▁identified ▁by ▁the ▁Internet ▁Watch ▁Foundation . ▁However , ▁no ▁saf egu ards ▁exist ▁to ▁stop ▁the ▁secret ▁list ▁of ▁blocked ▁sites ▁being ▁extended ▁to ▁include ▁sites ▁un related ▁to ▁child ▁por n ography . ▁This ▁had ▁led ▁to ▁criticism ▁of ▁C lean feed ' s ▁lack ▁of ▁trans par ency ▁which ▁gives ▁it ▁considerable ▁potential ▁for ▁broad ▁c ensor ship . ▁Further , ▁C lean feed ▁has ▁been ▁used ▁to ▁block ▁access ▁to ▁copy right - in fr ing ing ▁websites ▁after ▁a ▁court ▁order ▁in ▁ 2 0 1 1 ▁required ▁B T ▁to ▁block ▁access ▁to ▁New z B in 2 . ▁This ▁has ▁led ▁some ▁to ▁describe ▁C lean feed ▁as ▁the ▁most ▁perfectly ▁invisible ▁c ensor ship ▁mechanism ▁ever ▁invent ed ▁and ▁to ▁li