They are used internally, both by schools in targeting areas which need improvement and by local authorities in assessing the performance of schools.
A small sample of Scottish pupils - 15,000 for four year groups - also sit tests in English, maths and science, which are then used to judge the performance of the education system as a whole.
Results on pupils' performance at the end of their school careers, in Scottish standard and higher exams, are also not published in school league tables. Parents are given access to the information through school websites.
In Wales, a review of testing in 2004 recommended the abolition of national curriculum tests. Teacher assessment, moderated by teachers from nearby secondary schools, is replacing both the key stage 2 and 3 national tests.
The Welsh Assembly Government was concerned that the national tests could not be used by primaries to plan for pupils' future learning needs. It proposed replacing them with a new "skills test" to be taken in year five.
Schools would then analyse the results to plan pupils' priorities in year six. However, these tests are expected to be abandoned, the Welsh Assembly explaining that it did not want a "culture of testing" in schools. Teacher assessment will fill their place.