What would happen if we suddenly lost access to the internet? What if the online services we have come to rely upon were unavailable? And is this too far-fetched or a real possibility?

Regimes in countries such as Burma, Nepal and Iran have suspended or severely limited internet service at politically advantageous moments. The 2011 Egyptian revolution is the most recent and dramatic example of a government isolating an entire country from the internet. It happened in late January when, after several days of mass protests across the country, authorities made phone calls to the handful of internet service providers. Within minutes Egypt had disappeared from the internet, and mobile phone service was drastically reduced.

The revolution was facilitated in part by information and communication technologies - the internet, mobile phones, social networking sites etc - which the government severed with ease. Though the blackout lasted for five days, it did not stop the protests. In fact by closing off all virtual means of expression, it may have encouraged people out on to the streets to voice their discontent.

People around the world are asking if the same thing could happen in their country. As the internet has spread and become more complex, shutting it down at a global level has been made almost impossible. The underlying infrastructure is sufficiently widespread, interconnected and resilient to nudge such an idea into the realm of science fiction.

Yet it is clearly possible for a government to exert varying degrees of control over the internet connections that cross their country's border. Duplicating the Egyptian blackout in a country such as the United States or Britain is technically possible but highly unlikely for several reasons:

First, there are practical barriers to a blackout, as the internet infrastructure in most countries is almost entirely owned and operated by the private sector. Egypt has a relatively small number of mobile phone and internet service providers, making the blackout a simple affair. Countries with more competitive or independent telecom sectors are more resistant to attempts - be it from hackers or the government - to shut down, filter or otherwise meddle with the internet. Although complicity with repressive regimes is bad for business, telecom companies are often under legal and contractual obligations to comply. Any deviation could result in forfeiture of contracts, operating licences or long-term investments in the country.

Second, the political costs - domestic and international - would be high, particularly in countries with even vaguely democratic governments. Preventing access to the internet would be perceived as highly repressive and a denial of a service that is increasingly considered to be a human right. It would also be likely to inflame anti-government sentiment and galvanise protesters.

Third, the economic damage would be immense. For this reason - more than any other - a blackout is highly unlikely, particularly for an extended period. All organisations that rely on the internet would be forced to suspend business. Financial institutions would be unable to trade with the outside world, businesses would be isolated from supply chains, and any remaining lines of communication would be swamped as e-mail ground to a halt.

Even under extreme circumstances the Egyptian government could only sustain the blackout for five days. In many countries the internet is a core component of the critical national infrastructure, and there are fewer and fewer alternatives to the services it provides. Take it away - even through the use of legitimate emergency powers - and trouble will ensue.

For these reasons and others, a complete internet blackout is unlikely in most countries around the world - democratic or not. A localised "solution" is more probable, as in August, 2011, when the San Francisco transit agency turned off mobile phone service at several stations to limit communication between people protesting against the police shooting of a homeless man. In the aftermath of last summer's riots in Britain, Prime Minister David Cameron said that his government was looking at "whether it would be right to stop people communicating via these websites and services" - by which he meant Facebook, Twitter and BlackBerry Messenger. In both instances, cooler heads prevailed as public criticism mounted and unfavourable comparisons were drawn with countries such as China and Russia.

The lesson here is that governments of all kinds are willing to consider or implement drastic measures to stay in power, albeit in different ways according to varying political norms. Fears of hackers or cyber terrorists disabling or degrading the internet are overhyped. In reality the greater danger comes from misguided, short-sighted or reactive government policies.

Twitter: @ihavenet

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