DNA testing must be the biggest advance in criminal investigation since Sherlock Holmes lifted a magnifying glass to his eyeball.

For more than 100 years, the detective's most powerful tool in tracking criminals was to brush a bit of powder on to a fingerprint on a pistol left beside the body. If the gun was still smoking, it was an even bigger clue.

Before that it was a whistle to alert a copper's colleagues that a criminal was in full flight through the damp, fog-shrouded back streets.

Now, with the advances in modern science, they can take eyebrow tweezers to a hair at a crime scene and with a bit of DNA testing, presto, the crime is solved: it was Colonel Mustard, with a candlestick in the conservatory.

At least that's the theory. First they have to have a sample of the suspect's DNA to compare it with.

Which is probably why the police will welcome a suggestion to take DNA samples from every newborn to set up a national database.

A case of Big Brother picking on little baby brother? Why not? They are already tagging babies with an electronic ball and chain to make sure they are not kidnapped from the maternity wards.

An infant DNA - Dirty Nappy Assessment - database would certainly make life easier for the police, because then every suspect would be a toddler. CID - Criminal Infant Department - could interrogate the young suspects in their cots, deprive them of their rusks and hold back on the stewed apple and beef until they confess. And if that does not work, they simply make them stew in their Pampers until they beg and gurgle to be handcuffed and cleaned up.

If the infant hoodlums made a break for it in their prams, they could easily be pulled over by a pedal patrol car.

But is it right to have this hold over people from birth? Should we all be issued with identity cards so the State can track us to the very ends of our street?

I've had some bitter arguments - claws flashing, the lot - over this. I reckon if we have nothing to hide, there's nothing wrong with an ID card.

We have passports, driving licences - nowadays they even have pictures on - tax bills, business cards. Only the criminal need fear a national ID card.

Think of the time, money and fraud it would save. Youngsters could prove their age on the bus, or when asking for cigarettes and alcohol; shops would have it as proof of identity when making purchases.

Police would be able to know if someone is not who he claims to be and why would he make a false claim unless he was a wrongdoer.

But some people claim it is the thin end of the wedge, an infringement of civil liberties which would restrict their right to breathe, leave open the door for even greater control over us. It could even - God forbid - become George Orwell's 1984 nightmare of cameras in our own homes so the Government can watch our every move to see if we are being, and speaking, politically correct.

We'd have to hide in an alcove to have a crafty drag, creep into the wardrobe for a cuddle, or run a tap while we are muttering about the price of fish.

And while we are on about CCTV, there are those apparently upstanding citizens who feel it should not be watching over our towns and cities. Surely it makes the streets safer for us all, particularly old people, women and children.

A foolproof national ID card - with iris or thumbprint verification - could also take a great weight off our wallets. It could be the ID equivalent of a Swiss Army penknife, a multi-function card that acts as passport, driving licence, credit card, bus pass, library card, Netto discount pass, bingo membership, strip club entry card, dry cleaners ticket, all rolled into one.

You could throw all the rest away and not look as if you have a cabbage in your purse.

There must be one important restriction on it, however. It must not contain a tracking device so our spouses and bosses know when we are in the pub.

Updated: 09:08 Tuesday, September 30, 2003