More than a million illegal TV set-top boxes which allow consumers to stream content illegally have been sold in the UK in the last two years, investigators have warned.
Up to a quarter of Britons are estimated to access digital material illegally, but most people do not realise digital piracy could be putting them at risk, with dangers including inappropriate advertising that could be seen by young children, electrical safety associated with counterfeit parts and financial cyber crime.
A joint report by the Intellectual Property Office (IPO) and City of London Police, along with other organisations, said the organised criminal gangs behind it are profiting by millions of pounds from the fraud and are often associated with other serious crimes.
It warns of several concerning trends emerging that consumers need to be aware of.
These include the dark web and bitcoin boom, as more criminal gangs are using the dark web - hidden from the mainstream internet - to sell illicit information, such as the illegal software used to modify set-top boxes or the customer data they have acquired through malware.
It also warns that the availability of illegal add-ons to software has helped organised gangs reach a wider audience, but these add-ons have no parental controls or security standards.
Social media streaming is now overtaking web streaming, with most streaming now happening through social media platforms like Twitter and Facebook.
This is helping the criminals attract more viewers and is putting more users at risk of malware or security issues, the report said.
It also describes how social media commerce is replacing the pub or car boot sale.
Criminals selling illicit streaming devices are moving their business online, advertising on social media platforms and e-commerce sites, helping them remain anonymous and avoid detection.
The majority of criminals behind digital piracy make their money from advertising - typically banner ads or pop-up windows for casinos or dating sites, sometimes exposing children to inappropriate content.
Other money-making scams include subscription fees to access paid-for channels and charging other criminals to put malware on sites and hijack users' computers.
It is thought criminal gangs could be profiting by anything from tens of millions of pounds to hundreds of millions from these scams every year.
Digital piracy is one of the biggest challenges facing Britain's creative industries such as TV, film, music and publishing, along with the wider economy.
But investigators said the issue is widely misunderstood by the general public and is surrounded by many myths and misconceptions.
The report, Cracking Down On Digital Piracy, also collates expert insight from intellectual property protection organisation Fact, the Police Intellectual Property Crime Unit (PIPCU), Police Scotland and anti-piracy service Entura International.
Kieron Sharp, director general at Fact, said: "This report has come at a crucial time in our fight against digital piracy.
"A quarter of Brits access digital material illegally, and often don't realise the risks associated with that, for them and their families.
"Pirates are not Robin Hood characters, they are criminals who do it to make money through illicit means.
"As a result, the risks are high - inappropriate advertising that could be seen by young children, electrical safety associated with counterfeit parts, and financial cyber crime."
PIPCU head Detective Chief Inspector Pete Ratcliffe, said: "While it may be tempting for people to think they are getting a bargain when streaming illegally, it's important to remember that there are organised criminals behind it, often associated with other serious crimes.
"Pirating content is not a petty crime; from release groups, to site operators to set-top box wholesalers and distributors, there is an international criminal business model."