Nato officials have told the BBC their computers are under constant attack from organisations and individuals bent on trying to hack into their secrets. The attacks keep coming despite the establishment of a co-ordinated cyber defence policy with a quick-reaction cyber team on permanent standby. The cyber defence policy was set up after a wave of cyber attacks on Nato member Estonia in 2007, and more recent attacks on Georgia - so what are they defending against and how do they do it? Tower of Babel Nato's operational headquarters in Mons is a low, drab three-storey building - part of...