A National Curriculum may be a good idea but its implementation in England was a complete fiasco. Teachers were thrust into a maelstrom of change that created negative feelings of surprising intensity. The feeling was, and remains, that the professional opinions of teachers counted for nothing. Yes and more than a touch. At the same time, the very nature of the English system leaves a huge amount of autonomy to the teacher in the classroom.
Optimism can still reign.
I remain convinced that the format of the National Curriculum is fundamentally wrong but that it can be effectively ignored in the classroom by having clear programs of work that reach beyond its limited thinking. One of the core issues is a confusion between arithmetic and mathematics. Politicians express great concern at the lack of basic numeracy amongst the youth. They may very well be correct. That is not the same as a concern about mathematics.