‘I knew I was being followed’: Keira Knightley on her hacking nightmare – and new Stasi spy play The Lives of Others

<p>As the Oscar-winning Stasi surveillance film hits the stage, Knightley and co-star Luke Thompson talk about the paranoia at its heart, the cost of theatre tickets nowadays – and their fury at ringtones in the stalls</p><p></p><p>Unpacking assorted tubs of carrot stic