The scale of cyber crime is being underestimated as many businesses that fall victim are not reporting it for fear of damaging their reputation, the National Crime Agency (NCA) has warned.
Under-reporting of cyber crime is obscuring the understanding of its true scale and cost, with ransomware attacks - such as the one which caused disruption for major organisations including European bank BNP Paribas this week - becoming increasingly prevalent.
NCA deputy director general Matthew Horne said cyber attacks needed to be be viewed more widely as a security or criminal threat rather than as an IT issue.
"That's one of the main things we implore people to do - businesses just need to report it," he said.
"There's a range of actions that we can take, it doesn't have to go public just because somebody reports it. If they're not being reported that puts us very much on the back foot. We need that lead, that starting point to try and get some of the criminals involved.
"It needs to be viewed as a security and criminal act, not as an IT issue, and I think too often people think there's an IT fix for this."
Mr Horne was speaking as the NCA released its fourth annual public analysis of the nature and scale of serious and organised crime affecting the UK.
The National Strategic Assessment (NSA) said the primary threat to the UK from cyber crime continues to stem from Russian-speaking nations, but there are indications that the threat is increasingly global.
Other issues to be highlighted include the increase in modern slavery and people trafficking in the UK year on year.
However the true scale is said to be unknown, with the last Home Office figure of up to 13,000 in 2014 remaining the most robust assessment available, but described as "conservative" by Mr Horne.
"It is highly likely that the actual scale of modern slavery across victim and offender numbers, as well as incidence rates, has increased year-on-year. Analysis of drivers suggests this trend is likely to continue," the report said.
It also warned that a continued increase in global uncertainty and instability in 2017 and conflicts in countries such as Libya, Syria and Ukraine are likely to continue to create opportunities for criminal activity. Those forced to flee from such countries are vulnerable to labour and sexual exploitation, as well as debt bondage, both during their journeys and when housed in migrant camps.
Britain leaving the EU could also have an effect on serious and organised crime, as "many will strive to take advantage of the opportunities that Brexit might present".
"A lot of the vehicles that we use at the moment rely on European law, so there will always be concerns that if we didn't have these vehicles it would allow serious crime etc to have a better hold because we wouldn't be allowed to combat it so effectively," Mr Horne said.
But he added that tighter border controls could actually make it more difficult for criminals post-Brexit.
Other topics in the wide-ranging report include Child Sexual Exploitation and Abuse (CSEA), with changes in the use of technology such as the use of cloud storage described as having "transformed" its nature and enabled global contact between offenders and victims.
Meanwhile it said firearms offences increased by 7% in 2016 with the highest number of firearm discharge incidents since 2012/13.
It also warned that UK residents are now more likely to be a victim of fraud than any other type of crime.
Mr Horne added: "The NCA has a pivotal role in leading the UK's fight to cut serious and organised crime; this assessment provides us and our policing and law enforcement partners with a sound understanding of the threats we face.
"What is striking from this year's assessment are the themes running through the crime types. Organised criminal networks are using online methods to defraud and extort, but also facilitate the abuse of children and advertise the victims of human trafficking and modern slavery.
"Similarly, the threat from corruption encompasses a huge range of sectors and professional enablers, from bank insiders and accountants involved in high-end money laundering, through to port workers and delivery drivers facilitating drug trafficking.
"Criminal networks themselves are diversifying and it is not uncommon to find the same groups involved in trafficking people or illicit commodities, using the same methods or infrastructure.
"The NSA shows us how important a whole system approach to UK national security has become, with the NCA and its partners maximising our collective impact by working together to keep the public safe."