Mr Stock said that while traditional organised-crime groups were still heavily involved in drug trafficking and people smuggling, a new style of criminality was emerging.
He said cyber specialists were offering themselves for hire on the dark web and that they even had their own help-line and online reviews.
“The threat is becoming more complex, becoming more international than ever.
‘New business model of criminals’
“We see a completely new business model of criminals, organising themselves offering cybercrime as a service, money laundering as a service, and other support for criminal activity as a service in the underground economy,” he explained.
Cybercrime is now the biggest crime by volume in the UK, costing the economy an estimated £27 billion a year.
While some of the frauds involve sophisticated attacks on businesses and even government departments, most scams are committed against individuals using low-level phone- or email-phishing exercises.
Most attacks orchestrated overseas
Mr Stock said most of the attacks on British victims were orchestrated overseas in boiler rooms based in the developing world.
He said the challenge for law enforcement was trying to catch up with the criminals, who were dynamic and changed their tactics and techniques on a regular basis.
Mr Stock said the changing nature of crime meant police forces also had to adapt their tactics.
He said: “I was selected when I was a young police officer under different criteria. A police officer needed to be smart, needed to be strong, run fast to catch the criminals in a 100m race and should not wear glasses.
‘You still need a SWAT team’
“This has been changing. In today’s world our workforce is more diverse than it was when I was a young police officer.
“We need IT experts. Of course we are competing with the IT companies for the best talents in terms of IT skills.
“But the profile of an investigator in the IT world is very different to the SWAT team-oriented selection process that took place when I was a young police officer. So other skills matter.”
But he added: “You still need a SWAT team because if you are doing an arrest you want to do it in a way that you catch the criminal and you get all the evidence.”