More than 120 countries from all over the world are now actively engaged in either cyber warfare or cyber espionage against other states, according to research published today.

“Nations need to make significant investments in systems to deal with these attacks,” said Ian Brown, the Oxford Internet Institute research fellow who wrote the Virtual Criminology report.

The phenomenon is not going unregarded. Nato defence ministers met last month to discuss cyber defence after attacks on Estonian, US and UK systems earlier in the year.

Estonia’s problems were particularly severe. Co-ordinated spam attacks disrupted government systems, disabled news services and brought down online banking sites for almost 24 hours.

And the problem is only going to get worse.

Some states are still testing the boundaries, said International Institute for Counter-Terrorism research expert Yael Shahar.

“The whole sequence of events in Estonia looked a lot like something a government would do to check how much it could get away with,” she said.

Estonia has comparatively robust cyber defence systems. A similar attack on the UK might have more serious consequences, says the report, commissioned by McAfee.