The apparent cock up by the Cambridgeshire police in the UK over the search for two missing girls is a text book example of the short circuiting of human intelligence by placing too much dependence on a computer to sort out the "clues".

Perhaps much the same thing occurred when the US Central Intelligence Agency ignored vital clues pointing that terrorists were planning something major in the lead up to the September 11 attack on the World Trade Center.

One can only hope that individual police and investigators worldwide take heed from this unfortunate example and pay attention to the data being received, before it is fed into the computer.

Here's what apparently happened in the UK as far as I can put together from radio interviews and newspaper reports on the investigation into two missing girls, Jessica Chapman and Holly Wells. The two friends were reported missing on August 4 from their home village of Soham, Cambridgeshire.

A vacationing taxi driver in the area reported to police in Brecon, in Wales, on 7 August that he had spotted a car near Soham on the day of the disappearance in which a man was driving erratically while struggling with two children inside.

The Brecon police say they immediately reported the information that morning to the Cambridgeshire police in charge of the investigation. The taxi driver was not interviewed until August 11, a week after the disappearance, and was able to give an approximation of the make of the car, where it turned off the highway, and a sketchy description of the driver.

Cambridgeshire police say when they received the information it was immediately fed into a computer to be matched with other information. The computer apparently did not spit out the information until August 11 after matching it with other sightings of a green car in the area at the time. What probably happened is one of the persons in charge of screening the up to 7,000 tips a day being received by investigators, became an automation and just input the information in the computer without even registering its importance in his or her brain.

Now I cannot say what I would be like under that volume of information, but I believe an over dependence on a computer system led to a key tip in the case being buried.

Such a key tip should have immediately been referred to the top investigators in the case rather than being left to the computer to sort it out, police admit.

The computer screening system was apparently set up after police failed to connect several important sightings relating to Peter Sutcliffe, whose five-year killing spree as the "Yorkshire Ripper" was brought to an end in 1981.

Now the system seems to have taken over, at least in this one incidence, from the brains hired to do the job. As Hercule Poirot, Agatha Christie's fictional detective says, cases are solved with "little grey cells".

Here is some good advice on keeping e-mail spam at bay, provided by Sean Wallbridge, a self-described "computer guy" in Bermuda. Mr. Wallbridge is a computer technician.

"If you didn't subscribe, don't unsubscribe," Mr. Wallbridge said.

"Reputable online businesses want your repeat business and will ensure they don't irritate you in the process. By choosing remove or unsubscribe on spam mail and sending a return email or visiting a website, you are simply informing the spammer that your email address is valid and you will move even higher up the blast chain."

He advises people to ignore and delete the spam and not to dial the 900 number some of them provide either.

"It's just a trap to squeeze a couple more dollars out of you," he says.

"You can help your friends as well. If you have a joke and must share it with 100 of your friends, be sure and BCC all of them instead of including all of their addresses in the TO: line.

You never know where that message will get forwarded to and have its contents harvested. BCC messages are delivered individually and only you will be aware of who sent it."

He also recommends getting some anti-spam software. He has been testing a piece of software for Outlook called SpamNet by a company called CloudMark.

The software is free and is available for download at http://www.cloudmark.com/.

The software is available only for Outlook 2000 and Outlook XP but not Outlook Express.

"It takes a novel approach," Wallbridge said. "Any messages detected as spam are dumped into a spam folder. At this time it is finding roughly 75% of spam out there and filtering it out. The additional 25% is up to end users.

If a message creeps through, you simply choose to `Block' it and SpamNet is notified and updates its database so that it doesn't bother the next person.

Nice."

Tech Tattle deals with issues related to technology. Contact Ahmed at editoroffshoreon.com.