There are schools throughout the land in which the first lesson after lunch is a write-off for children who have spent the previous hour taking recreation-ground drugs through such contraptions, or just rolled up in Rizlas. They return to school wide-eyed - not in anticipation of whatever treats the National Curriculum might have in store for them that afternoon, but because they are doped.
Last week, the Government sought to address such problems. It set aside pounds 22.5m to fund three years of improved drugs education and launched a web site to help deliver it. It issued a document containing official guidelines on what schools should teach children about drugs, and how they should discipline drug-takers.
The document formalised the advice that had been offered to heads on Monday by Estelle Morris, the school standards minister, who had said that too many of them were too quick to expel pupils for such offences. Schools with "zero tolerance" policies should think again, for "drugs are a crime, but they are also a child welfare problem". Or, as the Government guidelines put it, schools that exclude drugs offenders more or less automatically are "failing to address the needs of those involved".
To many of us - particularly those of us who have teenage children - these moderate counsels seem reasonable and comforting. After all, there, but for the grace of God, or, if you prefer, statistical chance, goes one of our own children, expelled for what might be their one and only puff on a joint.
No, we don't want drugs in our children's lives, and we are very pleased when their head teachers do their bit to keep them out of their schools. But we also - most of us, I suspect - would like to see justice tempered, if not by mercy, at least by a sense of proportion.
AND YET, given New Labour's single-minded (though never singly expressed) determination to advance its idea of "education, education, education" through "zero tolerance", it seems rather odd that in this one matter alone - drugs in schools - it should explicitly repudiate it. Everywhere else, we are told, zero tolerance works. It works at a price, of course: not least in all those nervous breakdowns that precede or follow an Ofsted action. But those casualties are teachers, and it's a long time since anyone in government showed any sign of caring about them.
The price to be paid for enjoining zero tolerance of drugs in schools would be the cost - social, as well as financial - of a rise in the number of exclusions. That is a statistic that the Government does care about.
Zero tolerance of drugs in schools can be made to work. That much has been proved in the independent sector. At Rugby school, for example, the head's policy is to "expel anyone we catch". The result: "We used to have quite a lot of people smoking cannabis; now there are almost none."
Over 100 private schools now routinely carry out random testing of pupils - though they have different ways of reacting to proof positive that their pupils have been taking drugs. The tougher the regime, the smaller the problem. Only last month, a boy who was caught smoking cannabis at Eton was "asked to leave". In March, two older boys were sacked from the same school for a similar offence - even though it was committed a mile from the school. The drugs policy at Glenalmond is precise and jargon-free. In the words of its headmaster, Ian Templeton, "our policy is - one offence and you're out. That's it".
There is some toughness in state schools, too. King Edward VI Camp Hill School in Birmingham follows an equally hard line. It has expelled pupils for taking drugs. The head was quoted last week as saying: "My governors expect a hard line."
Whatever the rights, wrongs and absurdities of our laws relating to the use of drugs by adults, only the most anarchistic civil libertarian would argue that we should not do whatever we can to keep them out of the hands of children.
Cannabis may well be "safer than alcohol" as the New Scientist analysis concluded last year, but going into a lesson under the influence of either is not going to increase anyone's chances of examination success. Spaced- out pupils - like spaced-out prisoners - might be easier to control, but they don't do much for the school's position in the league tables, which allow little credit for the care, precision and accuracy of all those intricately drawn cannabis leaves which decorate their near-empty coursework folders.
Not all the drugs that children might take have a calming effect. Some induce wildly over-confident and bizarre behaviour, such as shrieking, giggling and running maniacally about while being completely tuned-out of what is going on around them. You might just as well try to start a conversation with a character in a radio play as talk to a child in such a state.
AND IT seems that even the "softest" drugs damage a child's educational chances. When the Head Masters' Conference - the association of independent schools' heads - met last month, it was addressed by a drugs expert who told them that "short-term memory, which is what young people need when they are learning, is the first thing to go when they take dope".
Recent surveys indicate that about 10 per cent of those preparing for GCSEs take drugs regularly, and at least 25 per cent of all 15- and 16- year-olds have experimented with illegal substances. Drug problems are believed to have some sort of effect on 20 per cent of all of those at school, including, in the words of the Schools Minister Charles Clarke, "ever younger children". So there were plenty of people ready to criticise Mrs Morris's remarks (gleefully summarised in the Daily Telegraph headline "Don't expel drug pupils, says minister") because they felt that she was, in the words of the Shadow Education Secretary, David Willetts, "undercutting the position" of head teachers.
From the reaction of some, you would have thought she was a latter-day Marie Antoinette who, when presented with a social problem, had said: "Let them smoke dope". But her tone did run counter to all the tough talking of a government that took the drugs problem so seriously that it appointed a tsar to deal with it. Furthermore, most state schools have been discreetly dealing with drugs in the way she advised for years. Why all the fuss now? A cynic might be tempted to suggest that if reducing drug abuse in schools were its first priority, the Government could achieve it by encouraging heads to expel drug-users. After all, another school would have to take those excluded.
This quietly happens now, and such children start with a clean slate. (So clean, in fact, that their original offences only emerge much later, when, say, the person who burns down one school's science block turns out to have been another school's excluded arsonist.) But many of those permanently excluded even once pretty soon drop out of the system, to become an even more expensive problem for social services and the police.
The Government knows it cannot eradicate drugs from the culture of our schools, but it can, at least, contain it there. A target which it can force schools and local authorities to meet is to reduce the number of permanent exclusions (for whatever offences), which reached 13,500 last year - a rise of 10,000 since 1990. This number is to be reduced by a third in the next four years - a figure that was, according to the National Association of Head Teachers, "plucked out of the air".
The truth is that Mrs Morris's carefully provocative remarks are more about exclusions than they are about drugs. They are a shot across the bows of those state school heads who might not have twigged that juvenile drug-taking is yet another problem they are expected to keep off our streets.
Tolerance has its price, too - and once again, it is our schools that are expected to pick up the tab.
But perhaps things could be worse. At least my flu is better. I'm over the coughing stage now, but I've been sniffing all week. None of the kids has asked me whether I have been "doing lines", though. Not yet, anyway.
The author teaches at an inner-city comprehensive.