russian cyber operatives attack britain media telecommunications energy sectors past year accord prepare remark head government main cyber defense agency ciaran martin chief executive national cyber security centre ncsc decline provide detail attack speech schedule wednesday london remark follow comment monday prime minister theresa may accuse russia spread disinformation meddle elections echo heat debate unite state allege russian interference 2016 presidential election russian strongly deny election interference unite state russian embassy washington immediately respond ask normal business hours comment martin remark ncsc branch gchq britain main signal intelligence agency operation year charge shore cyber security work wide range stakeholders martin say prepare remark confirm russian interference see national cyber security centre past year include attack uk media telecommunication energy sectors agency actively engage international partner industry civil society tackle threat russia say martin echo may comment russia try undermine international system information warfare cyber attack cyber security experts long worry attack electrical grids particular martin offer evidence allege russian attack succeed penetrate power systems critical infrastructure uk story refiled fix transpose letter acronym 5th paragraph russia attack energy telecom media britain government official