A group of PhD students, in another land, once turned up at a public examination armed with assault rifles. They then sat down and wrote examination papers on behalf of a class of pupils in the school. Understandably none of the invigilators objected.

Had it happened in Britain, some earnest primary head, clutching a copy of the Qualifications and Curriculum Authority booklet Assessment and Reporting Arrangements, would have rushed forward and said, “Now put away those guns and stop being silly, or you’ll all stay in at playtime”. That would have ended it, for page 21 of the national test manual for schools states quite clearly: “ensure no inappropriate support is given”. The gunmen would then have replied, “Fair enough, squire, mustn’t breach QCA guidelines”, and gone quietly home.

Most of the folklore alleging that schools are awash with cunning twisters inflating their league table performance by dubious practices is untrue. The QCA carries out spot checks of between 2,000 and 3,000 schools each year. This involves both local authority and QCA officers turning up unannounced either the week before testing, to check arrangements and security, or during the actual process, to see what is going on.

Completed test papers are also scrutinised carefully to see if there is anything fishy going on, such as lots of pupils answering in exactly the same way. Indeed, children are quick to blow the whistle to their parents about anything phoney when there are exams.

There have been very few cases of serious malpractice. Occasionally a headteacher has resigned following scrutiny, or a school’s results have been suspended, for example, if it varied the timetable of administration without permission. You cannot, off your own bat, simply give a test later in the week after all theother schools have done it.

Most of the malpractice detected, however, has involved relatively small misdemeanours, rather than crooked scheming. Some schools had inadequate security for storing the papers, but they had not actually leaked them. There were 208 investigations last year of tests at key stages 1, 2 and 3 - less than one per cent of all state and independent schools - and 182 were fully cleared of any suspicion. The rest were mainly guilty of minor infringements.

Nonetheless, despite the absence o any evidence of widespread fiddling, many primary schools are fearful of being accused of cheating unwittingly, anxious about whether or not they are giving the tests properly. Here are some possible pitfalls:

* No drifting over the amount of time allowed. Tests have been developed to be given in half an hour, or whatever, so extending the time is not permitted.

* Children must work on their own. One teacher used to say “some children have got big eyes” as a warning to those seeking to look over someone’s shoulder. The next generation will probably develop eyes on stalks. If you see someone skulking through Tesco, checking out trolleys, it is probably a teacher who has just been invigilating.

* Reading the test out loud for everyone is forbidden, since children are meant to work at their own pace, and this is deemed “inappropriate support”, as is pointing to a wrong answer and saying “think again” (subtle, eh?).

* Display material, such as multiplication tables, number squares, lists of word spellings and scientific terms must be removed. That also rules out big signs saying “The correct answer to question 2 is...”, or “If I wink my right eye the answer is A, while my left eye means B”.

* Aids such as a dictionary, a thesaurus or a spell-checker are restricted. Details are given in the manual. Briefly, the position is as follows: writing test - dictionary may be used, but not a thesaurus or word list. Reading test - dictionary, thesaurus, word list all banned. Maths and science - dictionary and thesaurus banned, but a bilingual dictionary or word list may be used by children with English as an additional language, provided they do not give any subject assistance.

Spell-checkers can be used in any test, except the spelling test (now there’s a surprise) and the level 6 English extension test.

* Mobile phones should be put in a pile and stamped on (not in QCA guidelines, just my own suggestion).

If PhD students with rifles do turn up, ask them if they have finished their thesis outline and literature review chapter. My experience with PhD students suggests that they will immediately turn to jelly and start making excuses about “problems with inter-library loans and international journals”. If that doesn’t work, bugger the manual. Just phone the QCA - from about 25 miles away.

Ted Wragg is professor of education at the University of Exeter