Businesses and law enforcement agencies are losing the "cyber arms race" with online criminals, the UK's National Crime Agency has warned.
The technical capabilities of criminal gangs are outpacing the UK's ability to deal with their threat, the NCA added.
It said there were 2.46 million "cyber incidents" last year, including 700,000 frauds - with the biggest threat coming from "a few hundred" criminals.
The government is to spend £1.9bn over the next five years on cyber-defences.
The NCA's annual assessment of cybercrime found a key threat to the UK comes from international gangs.
Some are so well-developed they run call centres and employ translators.