Falseacacia, these are professional people who haven't taken anything close to industrial action in 120 odd years, but have been driven to this action because they passionately believe that SATs don't contribute anything meaningful to a child's assessment - and just the opposite, in some cases.
In our school, we asked the children what they wanted to do. They wanted an internal assessment and their SATs breakfast club! Hardly cruel and calculated.
SATs in their present form, and the way they are used, damage some children's education. See my post of Sun 09-May-10 10:11:09 on this thread, and others' pots, for a few elaborations on why SATs/league tables are not a good form of assessment.
Using a test result to contribute to teacher assessment brings it in line with Key Stage 1 assessment, admission and Falseacia, whereby the test result is just one source of evidence a teacher uses to make a judgement. If a child's test result is inflated for any suspect reason this week, and was not in line with the myriad of other information teachers have regarding children, then it would simply be discounted.
"they do nothing but practice in school"
Thsi should not be the case - Y6 have a right to a broad and balanced curriculum - if they do nothing but practice, I would take it up with the individual school.