▁ 9 ▁December , ▁the ▁I WF ▁removed ▁the ▁article ▁from ▁its ▁black list , ▁stating : ▁" I WF ' s ▁overrid ing ▁objective ▁is ▁to ▁minim ise ▁the ▁avail ability ▁of ▁inde cent ▁images ▁of ▁children ▁on ▁the ▁Internet , ▁however , ▁on ▁this ▁occasion ▁our ▁efforts ▁have ▁had ▁the ▁opposite ▁effect ." ▁ ▁Public ▁Wi - Fi ▁ ▁The ▁vast ▁majority ▁of ▁the ▁Internet ▁access ▁provided ▁by ▁Wi - Fi ▁systems ▁in ▁public ▁places ▁in ▁the ▁UK ▁is ▁filtered ▁with ▁many ▁sites ▁being ▁blocked . ▁The ▁filtering ▁is ▁done ▁volunt arily ▁by ▁the ▁six ▁largest ▁prov iders ▁of ▁public ▁Wi - Fi : ▁Ar q iva , ▁B T , ▁Sky , ▁Nom ad ▁Digital , ▁Virgin ▁and ▁O 2 , ▁who ▁together ▁are ▁responsible ▁for ▁ 9 0 % ▁public ▁Wi - Fi . ▁The ▁filtering ▁was ▁introduced ▁as ▁a ▁result ▁of ▁an ▁agreement ▁put ▁in ▁place ▁in ▁November ▁ 2 0 1 3 ▁between ▁the ▁Government ▁and ▁the ▁Wi - Fi ▁prov iders . ▁Press ure ▁from ▁the ▁Government ▁and ▁the ▁UK ▁Council ▁for ▁Child ▁Internet ▁Saf ety ▁had ▁already ▁led ▁Virgin ▁and ▁O 2 ▁to ▁install ▁filtering ▁on ▁the ▁Wi - Fi ▁systems ▁on ▁the ▁London ▁Under ground ▁and ▁Mc Donald ' s ▁restaur ants , ▁but ▁half ▁of ▁all ▁public ▁Wi - Fi ▁networks ▁remained ▁un filter ed ▁in ▁September ▁ 2 0 1 3 . ▁ ▁" Over block ing " ▁is ▁a ▁problem ▁reported ▁with ▁public ▁Wi - Fi ▁filters . ▁Research ▁in ▁September