The lack of skilled workers is hampering Britain's ability to protect itself from costly internet attacks, according to spending watchdog the National Audit Office.
The number of IT and cyber security professionals in the UK has not increased in line with the growth of the internet and it could take two decades to fill the gap, the NAO said.
Government, education and business representatives have told the NAO the country lacks technical skills and the current pipeline of graduates will not meet demand.
The cost of cyber crime to Britain is currently thought to be up to £27bn a year.
NAO head Amyas Morse said: "The threat to cyber security is persistent and continually evolving.
"Business, government and the public must constantly be alert to the level of risk if they are to succeed in detecting and resisting the threat of cyber attack."
The Government's strategy has already started to deliver benefits, the NAO said, with the Serious Organised Crime Agency catching more than 2.3 million compromised debit or credit cards since 2011, preventing a potential loss of more than £500m.
But, the watchdog warned, ministers must address the country's current and future cyber security skills gap, which includes a need for psychologists and law enforcers, as well as technical staff.
Education officials interviewed by the NAO said it could take up to 20 years to address the skills gap at all levels of education.
The report on the NAO's review of the strategy for cyber security said: "Interviews with government, academia and business representatives confirmed that the UK lacks technical skills and that the current pipeline of graduates and practitioners would not meet demand.
"A number of government departments commented that the UK depended on a small number of highly skilled people to participate in developing international technical standards.
"Interviewees were concerned about a lack of promotion of science and technology subjects at school resulting in the reported lower uptake of computer science and technology courses by UK students."
A shortage of IT and computer science experts has been raised before by ministers, while attracting and retaining talent is also a concern.
In 2012, the Intelligence and Security Committee highlighted GCHQ's inability to retain internet specialists in the face of competition from the private sector.