But Scotland's underworld, enriched by three decades of lucrative but high-risk heroin smuggling, is now diversifying deep into the legitimate business world.
This week it emerged gangs, many Glasgow-based, had taken control of chunks of Scotland's booming payday loan market, putting the "extortion" firmly into extortionate interest rates.
No longer just looking for easy cash businesses - the traditional car washes and tanning salons - to launder their money, organised crime groups are looking for easy profits in new industries where their disrespect for the law gives them the edge.
Assistant Chief Constable Ruaraidh Nicolson, of Police Scotland, said: "People have got this view that organised crime is only involved in drugs and guns. But actually they are involved in much, much more than that. They are looking at the how to use the competitive advantage they have by not feeling bound by any legislation. They can undercut any legit company in this country and compete for contracts, for work, whatever and make very little contribution back into society and the economy."
Crime gangs have an advantage in the payday loan business. Operating from on-street premises in the poorer parts of Glasgow, they know few will feel able not to pay them back. Not for them, say sources, the niceties of rules set up by new regulator the Financial Conduct Authority (FCA). John Cuddihy, Police Scotland's head of organised crime and counter-terrorism, stressed that owning debt enabled gangsters to effectively own their clients. He said: "Crime groups will attempt to control the economic wellbeing of the entire community.
''We see individuals who have been put into a house owned by organised crime. If they fail to make the rent they are simply directed towards a payday loan from a firm owned and controlled by the same crime group."
The move into legitimate business may offer a safer form of business for gangs. Get caught dealing in drugs and you can face a decade in jail. But gangsters involved in evading hundreds of millions of pounds in landfill tax by building illegal tips risk far less: no criminal landfiller has been imprisoned to date.
But that does not mean Nicolson and Cuddihy - and their partners at Scottish Environment Protection Agency (Sepa)and the Crown Office - aren't vigilant.
Cuddihy said: "There are opportunities in green energy and waste management. They will move in to these areas because they are driven by supply, demand and profit. Profit is their god. Money is their god. That veneer of respectability is always there. But we have to look under that to find organised crime.
"Illegal landfill can have the same long-term impact as drugs. It will manifest itself in different ways ... in the pollution of our environment. But an organised crime group could not care less about the harm it causes."
Such semi-legitimate businesses may offer opportunities for Scotland's gangs but they do the same for the law enforcement agencies pursuing them. Because Police Scotland can now work with regulators - such as Sepa or the FCA - to target what are now the soft underbellies of criminality. Cuddihy said: "Other partners can target-harden sectors to make it difficult for organised crime to infiltrate them.
WASTE DISPOSAL AND ILLEGAL LANDFILL
Where there's muck, there's brass. Organised crime groups have long used skip hire and small-time waste disposal as a front. This kind of cash business was great for laundering income from drugs or racketeering. And it was also an area where cutting corners - essentially flytipping - provided a huge competitive advantage. However, soaring landfill taxes have provided what legitimate industry players believe is a real incentive to dig illegal tips across Scotland. Some unauthorised dumps - typically disused quarries, coal mines or railway cuttings - are on a major industrial scale. The creators are so brazen many people affected by the sites assume they are legitimate. The Scottish Environment Protection Agency has admitted it is now on the front line of the war against the underworld and is working increasingly closely with other parts of law enforcement to tackle this.
PUBS, CLUBS, SAUNAS AND ADULT ENTERTAINMENT
It won't surprise anyone that gangsters invest in pubs and clubs. The "local" owned by an underworld figure in poorer housing schemes is almost an organised crime cliche. Such businesses are classic fronts for criminals and also important bases, a marker of their control of their turf. But on a larger scale, major crime groups need influence, if not ownership, over the sector. Why? Because - aside from their own profits and cash sales - pubs and clubs can be important venues for illegal business, from drugs to prostitution.
Saunas and adult entertainment venues and businesses, including escort agencies, have traditionally been used as cover for narcotics and the vice business, either on site or elsewhere. Police in recent years have become particularly concerned with the danger of human trafficking involving those officially involved in the escort business as Scotland's prostitution moves off-street in to one-woman flats. The sector is increasingly - and sometimes controversially - receiving attention from law enforcement.
CAR WASHES, GARAGES
Dirty money is keeping Scotland's motors clean. For years carwashing has been one of the easiest way to launder money from organised crime. As viewers of the US TV drama Breaking Bad will have learned, it is the perfect cash business with low overheads and start-up investment costs - all you need is a tap, an easily drained bit of asphalt and some buckets. Crucially, it is impossible for any authority to check how many cars have actually been washed, and so it is easy to put cash from drug deals through the books of such a business. The mere hint of organised crime involvement in a local car wash makes it a difficult business to compete in. In recent years, car washes have also raised concerns that immigrant labour is being exploited.
Organised crime has a long-standing interest in the motor trade. However, new disruption tactics have seen regulators, such as the Vehicle and Operator Services Agency, used to strip the frontmen of organised crime of their licences to carry out MoTs or operate in the sector.
TAXIS AND BUSES
Taxis and more frequently private hire cars are another cash industry widely seen as being infiltrated by organised crime. The sector has also been the focus of considerable police and government action to clean it up in recent years, with fit-and-proper-person tests not just for drivers, but also for those operating radios in control centres. Taxis, however, aren't just good for money laundering. Like pubs and other front businesses, they can provide supposedly legitimate sources of personal income for gangland footsoldiers. Taxis can also play an important role in providing logistic support to drug-dealers, and act as a street-level symbol of control for organised crime groups on their turf.
Organised crime groups have also diversified into the bus industry since it was deregulated.
HAULAGE, WAREHOUSING, MARKETS AND LOGISTICS
Criminals need to move and market their illicit goods, from narcotics to counterfeit products. So they need all the same logistical expertise as any other business, from trucks to market stalls. And that means having access to, influence over or even control over firms in the industry. The traditional image of drugs, such as cocaine or heroin, is of a product imported in small batches. However, both Scottish and international crime groups increasingly produce drugs such as cannabis or so-called "legal highs" in Scotland. And that involves substantial movements of equipment and raw materials on an industrial scale.
Security is probably the industry most associated with organised criminals and the one subject to the most attention from law enforcement, with police intelligence now routinely shared with the Security Industry Authority, the sector's watchdog. Security is a classic cover for protection rackets but it also offers an opportunity for crime groups to legitimately employ their own muscle. Curiously, even a hint of an organised crime connection can improve the prospects of a security firm, since a "hard man" image is a market advantage. The signs put up by criminal security firms are also a potent symbol of turf control.
PRIVATE LETTING AND PROPERTY DEVELOPMENT
The property boom of the 2000s wasn't just felt by legitimate investors. Organised crime and its front companies and individuals have huge money in bricks and mortar. Property offers substantial opportunities for laundering money, not least through basic valuation frauds that create fake profits that can be used to explain income earned from illicit activities, especially when prices are rising. Private letting also provides substantial income and power for organised crime groups, helping to control clients and communities.
NAIL BARS, HAIRDRESSERS AND TANNING SALONS
Beauty businesses - rich in cash with no-one checking how many clients they really have - are classic fronts for organised crime groups. They also provide useful legitimate sources of income for the "wags" (wives and girlfriends) of gangsters - and are handy covers for the movement of drugs and the bulk chemicals and products needed to adulterate them for street resale. Local hairdressers, meanwhile, can also cement organised crime groups into communities in the same way as pubs, taxi firms or security agencies.
CHILDREN'S DAY CARE
Childcare may not seem the most obvious front for organised crime, but in fact it offers substantial opportunities for innocent-looking money-laundering as well as being a lucrative business in its own right, especially for unscrupulous entrepreneurs willing to ignore minimum wage and other restrictions. There have been cases of nurseries that have "ghost" children - clients that simply don't exist but pay hundreds of pounds in cash every week, at least according to their books.
Organised criminals have long been heavily involved in illegal loan sharking. According to the most recent police intelligence, in recent years they have also tapped into the booming business for payday loans. As The Herald revealed this week, such companies can often afford to offer more reasonable interest rates than their competitors. Why? Because the implicit threat of violence means they are more likely to collect their debts.
ORGANISED crime has long had its specialists, its chemists and accountants, its lawyers and PR men. But it also has access to those who know how to take over rivals, its mergers and acquisition experts.
John Cuddihy, of Police Scotland, explained: "Some of the more sophisticated groups, those that operate at the higher end of criminality, have professional facilitators. They will know how to carry out a takeover, sometimes a hostile takeover, sometimes done by two groups coming together because there is mutual benefit."
The Scottish Government estimates the cost to Scotland of organised crime at about £2 billion a year. The sheer scale of illicit business suggests gangs have access to considerable capital to take over smaller firms - or bribe or bully their way into access to larger ones.
The Scottish Business Resilience Centre, funded by police, government and private contributions, has experts too - those who can advise firms on how to protect themselves.
Assistant director Brian Gibson, a police officer seconded to the unit, said: "Business in Scotland is wide and varied but it is all at risk of criminal attack. For small and medium enterprises there is a real risk that a whole company could be attacked by a serious and organised crime gang. But even with your big mainstream companies there is the risk of somebody internal working against them, damaging them reputationally and financially."
For advice, see www.sbcc.org.uk