I don't have time to elaborate on this this morning but part of the government's propaganda about testing is to shield from people outside education the fact that broadly speaking there are two kinds of testing: one is called 'summative' - like GCSEs - at the end point of a chunk of learning, a be-all and end-all determiner of what has been learned; and 'formative' which involves (or should) a dialogue between teacher and learner and is itself part of learning, part of learning how to self-identify as a 'learner':
Here's wikipedia on 'formative assessment'. Please read so that at the very least, the government can't get away with claiming that their testing is the only possible testing.
My bottom line is that I don't think summative assessment is appropriate for primary aged children. It diverts learning away from investigation, interpretation, invention and co-operation.