From the NC website:
In the Schools white paper ‘The Importance of Teaching’ published on 22 November 2010 Ministers set out their plans to reduce the amount of guidance and materials offered to schools. They believe that schools should be free to use their own professional judgement about how they teach, without unnecessary prescription.
We have therefore removed non-statutory materials and guidance from the National Curriculum website and restructured the site accordingly.
All material previously available is preserved on the UK government web archive.
Since the above was written a new curriculum has been drawn up that will be introduced in September 2013 and will be effected in September 2014. During the one-year bridge between introduction and implementation we shall be linking lessons to the new curriculum and – where necessary – adapting them.