A depraved nation? Now let's be sensible ...: Leading article

Porn on the telly, sex on the Net, drugs in your next-door neighbour's window box ... where will it all end? To hear the outcry, you would think we were all slithering downwards into a mire of vile vice. Allow a little sex and drugs and we are off on a slippery slope. Before long we are skidding perilously about on an oily sludge of depravity.

Only there is no slope, and it isn't slippery. Just because people grow cannabis at home doesn't mean they are destined to become heroin addicts. Just because pornographic movies are broadcast on satellite television, that does not mean we should fear an imminent social collapse into an orgy of rape, abuse and indecency.

We all do it: that is, we accept unthinkingly the idea that one small step inevitable leads to a second, larger one; as if a single whisky is always followed by a double. But it isn't true. On so many of these questions - drugs, pornography, acceptable sexual behaviour, swearing in public, drinking - we decide as a society where to draw the line. Sometimes the line turns out to be in the wrong place - as it did in 1966 on the obscenity law, for example. So we move the line, either by legislation, or, more often, simply by tolerating change. It is ludicrous to pretend that every liberalising shift will unleash immoral forces that threaten to overwhelm us all. Slapdash slippery-slope arguments often end up as a feeble defence of impractical positions on social morality.

Take marijuana. The fact that so many people are now growing marijuana in their back gardens and hanging baskets should not bother anyone in the slightest, least of all the hard-pressed constabulary. In fact, it would be better to allow people to grow marijuana for their own consumption, since it undermines trade in a drug that is anyway less harmful to individual health than cigarettes and far less socially destructive than alcohol. The only serious social objection to marijuana is that the people who smoke it tend to sit around giggling inanely, but at least that's preferable to drunks who bray at tasteless jokes, leer at passing women, and threaten anyone who looks unimpressed.

Nor is there any reason to believe that liberalisation of soft drugs would legitimise and encourage hard drug use. Quite the contrary. By drawing the line in a sensible place (between relatively harmless recreational soft drugs and deeply dangerous hard drugs) rather than in a silly indefensible place (between nicotine and marijuana), we could do a lot to legitimise the law.

The same is true of porn on television. Why should Virginia Bottomley care what other adults want to watch, so long as it does her no harm at all? Where it is impossible for parents to control access by their children, it is possible to see her problem.

But broadcasting and personal computer technology allow all kinds of simple barriers that are more effective than a video shop owner and ID cards. There is a demand for sex on the telly, as Channel 5 is demonstrating by its professed desire to run a little light erotica in the wee hours. Is there any evidence that our European neighbours suffer from a more depraved lifestyle than we, simply because pornography is legally available?

Mrs Bottomley's opposition to the "squalid diet of filth and degradation" available in Europe flows from the same neurotic, uptight attitude that sex should be endured for England's sake. Porn that is violent and grossly exploitative should be banned, not because it is "filthy" in the sexual sense, but because it hurts people. It obviously follows that pornography that uses children is doubly criminal. But that proves the point: we know where the line should be drawn, and it is not so hard to draw it. Drawing the line in the wrong place simply makes the law look foolish, and encourages perfectly normal people to step around it.

There is no slippery slope between willing erotica and violent videos. Broadcasting consensual sex games will not encourage men to commit violent rapes. Nor is there immense public demand for sex on every channel at every hour of the day. If porn channels were available in Britain, there might be a flurry of interest at first; then when the novelty wore off, most of us would find far more interesting things to watch or do. With porn, just as with soft drugs, there is no welling tide behind the supposed floodgates. Those who enjoy the occasional joint or the odd erotic movie would be able to do so with greater ease, and without fear of prosecution. But legalising cannabis and porn channels would not be the trigger for sex and drugs to dominate all our lives. In fact, there is some reason for thinking that if we were to draw the line in the right place, people would become less excitable about these subjects altogether.

Of course, there need to be laws that restrict our use of addictive substances, and our social and sexual interactions with each other. Laws that restrict our freedom of choice are fine in areas where we need protection from one another. No responsible adult wants to encourage a society that allows drug barons to prey on teenagers and push them into addictions that destroy their lives. Nor would they endorse the widespread distribution of material (sexual or non-sexual) that harms people or incites them to violence.

We just need to get the balance right. Stopping people doing things and watching things which harm nobody, and which huge swathes of people across the country regard as wholly acceptable, is wrong. As a certain eminent baroness, once prime minister, used to say: the nation does not need nannying.