‘The Purge’ suggests that for one night every year, citizens can take up knives and guns to kill anyone they choose without legal reprisals.

“Gather me into the artifice of eternity,” pleads the narrator of WB Yeats’ ‘Sailing to Byzantium’, but Eleanor (Saoirse Ronan) and Clara (Gemma Arterton) are struggling to cope with the reality of a rather prosaic immortality in Byzantium (15A).