The annual Virtual Criminology Report, which draws on interviews with senior staff at organisations such as the Serious Organised Crime Agency, the United Nations and the FBI, found that a number of countries were providing “political cover” for criminals against attempts at prosecution by other nations.

The report said: “The cyber-kingpins remain at large while minor mules are caught and brought to rights. Some governments are guilty of protecting their in-country offenders.”

The study found that Russia and China were among those harbouring internet criminal networks, and that they are “especially reluctant to co-operate with foreign law enforcement bodies for reputation and intelligence reasons”.

“A lot of it is corruption,” said Dr Ian Brown, of the University of Oxford, one of the report’s authors. “In Russia, it is in regional governments and police agencies, there are connections between the cyber-criminals in those areas.”

The report also sounded a warning about the growing threat of cyberterrorism, saying internet hackers will soon become “powerful enough to launch attacks that will damage and destroy critical national infrastructure”, including the National Grid, gas and water supplies, and bank payment systems.

The British Government said earlier this year that key national utilities were under attack thousands of times a day from web criminals and terrorists. Dr Brown said that without significant improvements to the security in the next five years, these attempts to shut down vital systems like the National Grid could succeed.

Security experts say that any successful attack would be likely to result from a hacker exploiting the part of a computer system that was connected to the internet - known as a port - and are concerned that British companies were not doing enough to protect their networks.

The Virtual Criminology Report, commissioned by McAfee, the computer security firm, found that the volume of internet viruses, one of the web criminal’s weapons of choice, had almost tripled in the last year, the vast majority of them attributed to attempts at soliciting or stealing money from victims.

Dave De Walt, Chief Executive at McAfee, said: “We’ve seen a clear evolution from basement teenagers who were written about for many years to sophisticated cybercrime groups.”

The report found that there was growing evidence of “cyberespionage”, with states responsible for co-ordinating internet attacks on other countries. India and Belgium are the latest countries to have complained that they had come under web attacks believed to have originated in China.

Researchers said that they had uncovered evidence of Russia having carried out state-sponsored cyberwarfare against Georgia by attacking government computer networks during the recent conflict.

The study found that the current economic downturn is exacerbating the problem, pointing to an increase in the number of fake e-mails purporting be from banks, and the likelihood that more people are being tempted by “get rich quick” schemes.

“Recession is fertile ground for criminal activity as fraudsters clamour to capitalise on rising use of the internet and the climate of fear and anxiety,” the report said.

Security experts said that the trade in bank information and personal identities over the web continued to thrive. Credit card numbers can currently be bought in internet forums for as little as 30p.

Matthew Bevan, a reformed hacker who now works as a computer consultant, told researchers: “The credit crunch is also hitting the cybercriminals – they’ll be working even harder to make money.”

The Chinese Embassy in London said: “These kinds of allegations are not new, China has been accused on different occasions in the past, but every time they have failed to produce the evidence. China is also a victim of these virtual attacks, and we hope to work with other countries other countries to fight against it.”