Deciding marks by coin toss wouldn't be much worse

After last year's fiasco, 11-year-olds and their anxious parents and teachers must now reconcile themselves to the fact that only just over half of grades in English writing tests are correct.

The scale of the problem is staggering and far worse than even the most pessimistic critics ever imagined.

Previous estimates have suggested that up to a third of grades in Sats may be unreliable. In fact, deciding children's grades on the toss of a coin would not be significantly worse. The situation is compounded by the fact that the final year of primary education in far too many English schools has become little more than a soulless factory-like experience in which children are relentlessly drilled in preparation for their tests.

After such a miserable time the least they deserve is to receive accurate grades.

The results are important to children's future education - secondary schools use Sats to give an indication of a child's ability when deciding on setting and streaming.

The grades are also crucial to schools, forming the basis for league tables, Ofsted judgments and scores against government targets. Indeed, it is this pressure to achieve good Sats scores which leads too many teachers to give up on a rounded education and focus entirely on coaching children for tests.

Faced with such a shambles, Children's Secretary Ed Balls should recognise that the current Sats regime is no longer fit for purpose - if it ever was.

Of course children must be assessed in order to help them make progress, and the public needs some assurances over the quality of the national education system, both of which testing can provide.

But inaccuracy of this magnitude, renders Sats - in English, at least -worse than useless. It's time they were scrapped.