Results in the science sample tests rebounded this year following a sharp fall when they were introduced in 2010.

In 2009 - the last year of the national curriculum test in science, which was taken by all Year 6 pupils - 88 per cent of pupils were assessed at level 4.

But in 2010, when sample tests replaced the national tests taken by all pupils, the scores dropped to 81 per cent reaching level 4. This year, however, 85 per cent achieved level 4.

The wobble is in stark contrast to teacher assessment scores for science, which have stayed almost static throughout this time - at 86 per cent in 2009 and 85 per cent in 2010 and 2011.

The science test was dropped after a report commissioned by the previous Labour government pointed out that it was not as good at predicting how well children would do in science at secondary school as the English and maths tests.

The hope was that by dropping the emphasis on pencil-and-paper tests, more practical and investigative science could be carried out in primary schools.

The sharp downturn in 2010 was attributed to more focus being placed on English and maths - which remained as the two subjects for which individual schools are held accountable.

Some said that the change in results revealed that in previous years, the science scores had been inflated through teaching to the test.

The Bew inquiry into testing at key stage 2 recommended that the combination of teacher assessment and sample testing remains for science. The Government has accepted this recommendation and has said it will look into developing a system of pupil-level science sampling in future.