Children of Men - How was the equilibrium established?

Enigma code (mystery): the questions which are raised by 'clues' in the text.


In the opening ten minutes of the film Children of Men we find out that the film is sent in London 2027 and that the youngest person in the world died at age eighteen.  This suggests that women all over the the world are infertile.  We find out that many issues are taking place in London such as the refugees, as this is what we see in the news report that UK borders are closed.  The film shows London as more advanced in terms of technology.  For example on the bus the posters are moving and on buildings aswell whereas today our technology has not reached to that extent.
The protagonist of the film is Theo who is first seen as careless and not being affected by the news story about baby Diego's death.  This is clearly conveyed when he enters the coffee shop which is packed with people watching the news about the babies death, however Theo pushes to the front gets his coffee and walks out not even interested.  As soon as Theo walks out of the shop and stops to put some alcohol in his coffee, a bomb blast takes place in the coffee shop - this is where an enigma is created.  This leaves us thinking: who planted the bomb? What was the reason for it?  Well, we find out later in the film that a gang of people called 'Fishes' had a leader who was once Theo's girlfriend planted many bombs in London.  This made us as the audience think she planted the bomb, however we later realise she had nothing to do with it but the Government did.