It seems that Twitter has come under co-ordinated attack from hackers calling themselves the “Iranian Cyber Army”.

It will be remembered that Twitter was the means by which the world found out about demonstrations against the current administration in Tehran.

Cyberwarfare is no longer science fiction. It is happening – quite a lot in fact. It ranges from minor hacking for data to full scale “denial of service” attacks to cripple a whole network – the cyberwarfare equivalent to carpet bombing – such as that which is said to have preceded the South Ossetia War in 2008.

A relatively obscure text from the nation that gave us Sun Tzu provides the theory behind cyberwarfare. In Unrestricted Warfare, two Chinese colonels reverse von Clausewitz’s classic “war is the continuation of politics by other means”.

Now politics is the continuation of war by other means. Indeed almost anything can be war by other means. Economics can be war: cripple someone’s economy and you cripple his ability to wage war.

The surest way to cripple an economy is to cripple the computer networks on which business now depends.

Given that most small businesses are reliant on computers connected to the internet for at least some of their operations, it is not merely possible but probable that, sooner or later, most of us will be either the targets of cyber attacks or, more likely, suffer collateral damage.

We need to get into the habit of taking practical countermeasures – now.

1   Modern IT is so convenient that we often forget to ask if it is necessarily the best way of doing business? For example, are we losing customers when we lose human contact? We should make a point of reviewing all aspects of our IT dependency on a regular basis, and not just for security reasons.

2   Most commercial security software will be little defence against a major cyber attack specifically designed by experts – but up to date security is still essential as protection against bottom-feeding hackers and their unending attempts to steal information. If you have good security software, you may not know how good it is, because you may never know how many attempted thefts it has foiled.

3   Back up everything – at least twice – and then lock a back up copy away somewhere, preferably at a different location in case your premises are destroyed by fire or some such horror.

4   Finally, as citizens rather than businessmen, we should oppose the jailing of talented hackers like Gary McKinnon, so long as there is nothing malicious in their offences. Our governments should be employing people like that to defend us.