And if you see how nothing in Germany could be decided that affects the UK, what do you think would happen if German and French banks had refused to fund bailouts for the less responsible EU companies? No effects felt outside of Germany?
And I did not say that the decisions in Germany (or any other country) can not influence the situation of other countries, I said they can not influence them to a degree that justifies espionage. So how does you example apply? Germany and France are free to support or not support what ever they want. How would having known such decisions before they were publicly announced made any difference?
Besides, the prisoners dilemma assumes there are no penalties for betrayal and that certainly is not the case for international politics.
[1] https://en.wikipedia.org/wiki/Prisoner%27s_dilemma#The_itera...
And I see neither how something we decide in Germany may affect the UK to a degree that justifies espionage, nor do I see how decision of the UK may impact Germany to such a degree. Can you think of a good example?