Who on earth can they be, these devilishly clever authors of malicious computer programmes - known as malware - who are apparently constantly attacking our systems both at home and at work?

Whoever they are, there are a lot of them: brainy people who get up each morning, perhaps in South America, or Eastern Europe, and put in a day's work springing crafty cyber-snares for the rest of us to fall into.

David Emm, senior technology consultant at the fast-growing Russian virus fighting company, Kaspersky Lab, which now employs 31 people in Harwell, said: "Online pickpocketing is growing.

"There are now about 500 new threats to your computer's health, and possibly your wealth, every day."

Kaspersky Lab, now with branches in 12 countries, a worldwide payroll of 850 people, and annual turnover topping £42m, has its roots back in Soviet Russia.

It was born in 1989 in Moscow, just before the Gorbachev-led Perestroika ended the Communist regime.

Mr Emm said: "In a way, our thinking is coloured by that change in Russia. The company adapted to the new, changed world then, although the firm was not formally registered in Moscow until 1997."

The idea of policing the cyberspace in the Soviet Union was the brainchild of Eugene Kaspersky, the hands-on chief executive of Kaspersky Lab, and his former wife Natalia.

Now Kaspersky sells security ware to both businesses and personal PC users almost exclusively through third parties, including such giants as Microsoft.

Mr Emm said: "Cyberthreats are not just getting more sophisticated, there are more of them too. Kaspersky Lab anti-virus database now holds more than 340,000 records."

In the past, computer viruses and worms were designed more or less to cause mischief.

Unfortunately, the new generation of so-called Trojans - named after the famous wooden horse smuggled into ancient Troy to wage war and destruction from within - are designed to make money for their masters by stealing information.

Mr Emm added: "Trojans are referred to as spyware. They're installed stealthily without your knowledge or consent, and they monitor your actions day after day.

"They are deliberately designed to be inconspicuous and they hide their tracks using programs called rootkits. As a result you can't see them with the naked eye. Everything appears to run normally."

But why would anyone buy Kampersky anti-virus software when such firewalls are available to download free?

Company spokesman Kersten Reiners answered the question by referring me to a report in computer consumer magazine PCPro.

It read: "When we reviewed Kaspersky's security suite last August we admired its antivirus component but questioned whether it was worth paying for.

"This month we have our answer: freewareAntiVir achieved an impressive 92 per cent detection rate, but Kaspersky Anti-Virus 7 managed to find and remove an incredible 98 per cent of the malware in our test."

Wormed The company also offers an expert telephone advice line, and a service that checks your computer every hour 24 hours for malingering nasties that may have wormed their way into your machine.

Kaspersky works with large credit card companies to thwart thieves. Like credit card companies, it has developed so-called heuristic' systems which analyse users' habits online and pick up any unusual behaviour.

In this regard, how many of us have wondered how criminals obtained our credit card details? Could it have been by hacking into our computers?

I remember a telephone call from American Express in which a representative sounded surprised that I was in England.

She said: "Someone is going round Amsterdam at this minute using a fake version of your card. So far they have spent £3,000."

The card company picked up the unusual' behaviour and bore the cost without a murmur. Common forms of attack on large businesses include outrageous cases of blackmail, in which a company may learn that all its data will disappear unless it pays a huge sum, up to £55,000 a week!

Then there are so-called phishing' attacks, in which computer users finds themselves being referred to an authentic looking site, perhaps claiming to belong to their bank, which requests personal information such as PIN numbers.

Even less edifying are criminals who blackmail individuals by simply threatening to report personal data, or worse, itineraries of unappetising sites that a computer user may have visited.

Mr Emm gave some simple guidelines of dos and don'ts to guard against email attack: l Be wary of emails asking for personal information l Don't click on links in HTML emails. Instead type the URL into your web browser.

l Check bank accounts and credit and debit card accounts regularly to make sure all transactions can be accounted for. Thieves often take only relatively small amounts each month, so as not to arouse suspicion.

Contact: 0871 789 1631, visit www.kaspersky.co.uk