Thats what David Cameron said
A variant of "that's what she said." Instead of referring to sexual connotations, it is used to refer to badly managing a government or lying/ballshiting to the general public.
Person 1: Im good at maths
Person 2: Thats what David Cameron said
Person 1: I can help you
Person 2: Thats what David Cameron said
Person 1: I want the Best for society
Person 2: Thats what David Cameron said
Person 2: Thats what David Cameron said
Person 1: I can help you
Person 2: Thats what David Cameron said
Person 1: I want the Best for society
Person 2: Thats what David Cameron said