The National Curriculum
The National Curriculum has to be taught to children in state schools in England between the ages of 5 and 16 (ie Key Stage 1 to Key Stage 4), except in special circumstances. Private schools (which are often referred to as public schools) do not have to follow the National Curriculum, though many choose to do so.
In addition to the National Curriculum the government has produced very detailed guidance on the teaching of literacy and numeracy in the forms of The National Literacy Strategy and The National Numeracy Strategy. Whilst these are not statutory, state schools in England are expected to adhere to them or need to be able to demonstrate that they are achieving 'better results' than would be expected using another approach.
National tests (SATs) are carried out at the end of Key Stages 1, 2 & 3, to see how the children (and their school) are performing in relation to national expectations (which are set out in The National Curriculum). League tables are produced to show how schools are performing, based on their pupils' SATs results.