Cheapest pre-order I can see, around £15-16 elsewhere. Also part of their "2 for £20" deal, plus 4% Quidco as well.
Evelyn Salt (Angelina Jolie) is a CIA officer that is identified by a defector as a Russian sleeper spy and is accused of plotting the assassination of the visiting Russian President. Her CIA superiors are quickly convinced that she is involved in an international conspiracy and make her the target of an intense hunt. Evelyn risks her own life and that of her husband to prove that someone else is the traitor.