The Qualifications and Curriculum Authority received 147 complaints about maladministration and malpractice in last year’s tests for seven, 11 and 14-year-olds. In 1999 they received 204.

A QCA spokeswoman said the majority of cases did not warrant an investigation. Ten per cent led to adjustments in individual final marks but in only one case were the results of the whole school annulled. In 1990 8 per cent of complaints resulted in whole-school re-marks.

The queries from parents, pupils, teachers, councils and marking agencies covered a range of issues, from schools failing to keep test papers in a locked cupboard to teachers giving extra time to pupils to finish questions.

The National Association of Primary Head Teachers claims bending of the ules is widespread in the tests because of the pressure of performance tables.

Nearly three-quarters of the cases reported last year related to key stage 2 tests for 11-year-olds which are published in primary league tables.

About 3,000 spot-checks each year are carried out by the QCA and local authorities. Officers turn up either the week before testing or during the actual process.

Completed test papers are also scrutinised to see if many pupils are answering the questions in exactly the same way.

The worst example of widespread cheating at key stage 2 happened two years ago when half the schools in the London borough of Wandsworth were given leaked details of a test.

Information was passed to teachers from officers at the education authority that the reading paper would involve a discussion of the Little Miss Muffet nursery rhyme and a factual piece about spiders.