There is a conflict, it often seems, between science and freedom. The more scientists discover about us, down to microscopic genetic tendencies we might have to aggressive impulses or early dementia, the less secure we feel in our liberties.

Our secrets are not safe, not even the ones we didn’t know ourselves. The more such things are understood and recorded and electronically shared, the more anxious we feel. This information is power, for better or worse, and people will be tempted to seize it. That is no reason to become a Luddite, but it certainly ought to make us all particularly watchful about our liberties.

So it came as a toast-dropping surprise to hear a distinguished appeal court judge recommend on the Today programme last week that every person in this country ought to be put on the criminal DNA database, along for good measure with every foreign visitor. One might expect some hanging and flogging judge (if there are any left) to take an authoritarian line, but Lord Justice Sedley is known for his interest in human rights.

One of his concerns is that ethnic minorities are overrepresented on the database, and that this is unfair. To make things fair, he thinks we should all be rounded up and have our mouths swabbed, man, woman and child, so things are equally unfair for all of us.

It should come as no surprise to learn that Stephen Sedley once belonged to the Communist party. Compulsory equality is at odds with personal freedom, and while Sedley is no longer a party member, he has grandiose ideas; he lists “changing the world” as an interest in Who’s Who.

Admittedly there might be a case to be made for having everyone’s DNA profile available to the police; it might help to solve more crimes. However, Britain already has the world’s largest DNA database, yet since it was introduced 12 years ago the rate of solving crime has remained unchanged.

Much more powerful is the case the other way. Putting the entire population on the database is an abuse of the freedom of the individual in itself. It offers terrible and so far unimagined abuses in the future; the better the DNA code can be read, the more complex and extreme the abuses could be. The risks of conspiracy would conspire with the greater risks of cockup.

We know that British bureaucrats and politicians have an appalling record with computers and personal information. The massive NHS database is a shameful case in point. Everyone in their right minds will try to stay off it. So too are the many errors of the tax and benefit system, which makes mistakes that are almost tragic when poor people suddenly find themselves in serious debt. Only last week the parliamentary public accounts committee found that a new subsidy due to English farmers had been grotesquely mishandled.

And these are the people - the politicians and the apparatchiks - that Sedley proposes to let loose on the intimate details of our DNA! If Whitehall cannot manage the details of a few farmers one dreads to think what the nomenklatura would do with about 90m new genetic profiles, or indeed with our NHS medical details. Even when they did not abuse, lose, confuse or accidentally reveal our secrets themselves, other people would most certainly steal them to abuse them, through hacking or corruption as well as inadequate security.

That is surely why the government proposes to remove details of the children of celebrities from an education database. It takes breathtaking ignorance of what happens to powerful information in the real world to suggest that everyone’s most sensitive details should be exposed to such serious risk.

Last week, for instance, it emerged that the Chinese are particularly good at hacking into other countries’ sensitive information, including our own military and Foreign Office computers. Ministers tried to play this down, much as they tried to ignore a Chinese cyber-attack on the House of Commons computer last year.

In view of these embarrassments, you might imagine the government would stand firm against Sedley. You might expect new Labour’s self-styled champions of human rights to cut back the criminal database, by about 1m, to remove everyone except those convicted of a crime. On the contrary, ministers are “broadly sympathetic”, to Sedley’s suggestion, according to Tony McNulty, the security minister. He said the government has no plans to put everyone on the database, but the truth is that the Home Office is planning to add to it considerably. A review will be published in February.

It is wonderful to know so much about genetics. The risk that this knowledge might be abused must always be weighed against the advantages it offers. Here what is needed is practical evidence, not arguments of principle. In the criminal DNA profile case, the risks quite clearly outweigh the rewards. Nobody can guess at what DNA profiles will soon reveal and how that knowledge could be abused; having some criminals at large is one of the many prices of freedom.

However, in the case of hybrid embryos, which aroused fury last week - much more, oddly, than the DNA database - the risk-reward relationship is the other way around. It is alarming to think that geneticists are going to create embryos that are part human and part animal; terrible things might conceivably happen. If one distrusts Whitehall, why should one trust the men and women in white coats?

The answer is purely practical, based on experience. Scientists have a hugely better reputation than politicians or bureaucrats for intelligence, integrity, competence, truth-telling and sticking to the rules, especially when they are independent of the state. The hybrid experiments will not affect everybody; in fact they won’t even affect individual people. They may help to heal people with terrible diseases, and if they don’t the only loss will be minute quantities of living tissue and a great deal of time, effort and hope.

It is conceivable that knowledge discovered in these experiments might somehow be used against persons unknown. But the conflict in such matters is not between science and freedom, but between freedom and the abuse of science.

minette.marrin@sunday-times.co.uk

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