Vulnerable people were forced to work for the Rooney clan for little or no wages, while their pay-masters lived a life of lavish luxury.
The 11 gang-members, convicted of fraud and slavery charges, enjoyed holidays to Barbados and cosmetic surgery and even shelled out on a Manchester United soccer school, earned off the backs of their workers.
Among them was John Rooney, 53, of Chantry Croft, Pontefract, who was convicted of two counts of conspiring to require a person to perform forced or compulsory labour.
Operating from sites in Lincolnshire, the group targeted victims who were homeless, had learning disabilities or complex drug and alcohol issues.
The men, aged 18 to 63, were freed after raids by Lincolnshire Police and the National Crime Agency, carried out in 2014.
One of the victims was found to have been working for the family for 26 years.
Some of the gang also targeted four elderly home-owners, getting them to sign over properties into their names and selling three on for profit - one for £250,000.
One the householders ended up dying without his family knowing. It was only when contacted police they discovered they had missed his funeral.
After four trials resulting in convictions, the full scale of the offending can now finally be revealed after a ruling at Nottingham Crown Court on Friday.
Judge Timothy Spencer QC said: "After careful consideration, I'm quite satisfied the public interest lies in these matters being reported."
Members of the family would go looking for victims on the streets, hostels and shelters, offering work for food and accommodation.
But at sites in Drinsey Nook and Washingborough, the offers of fair work for fair pay were exposed as lies.
However, it was through false promises, drugs, alcohol and violence, family members made sure they kept their victims "financially-trapped" and under total control.
Labourers were forced to live in shabby run-down caravans, or in stables next to kennels, with little or no access to basics such as heating, water and toilets.
Some were forced to squat in woods behind their living areas, while electricity was "dangerously" tapped from a nearby pylon.
In all, 18 men were forced to work at the sites or for the Rooneys' businesses, repairing properties and tarmacking drives.
Most told how they were never given safety equipment or the right clothing.
The police said victims were also "poorly fed" and often went hungry - or were given the "family's left-overs", even though they were worked for hours on hard, manual tasks.
If victims complained, the gang would say they still owed money and would claim more labour to pay off the bogus debts.
The heartless gang provided alcohol and drugs as part of what prosecutors had described as a "grooming" process.
But as their hold on the victims increased, that illicit supply gave the clan an ever-tighter hold over their victims, including their bank accounts.
In some cases, the accounts were used to pay for gym memberships, soccer schools and building materials to supply the business.
The Rooneys also used "threats" and "violence", including punishment beatings, and the victims were denied medical help for their injuries and ailments.
The impact on the victims was severe, with many suffering mental and physical torment during their "gruelling and emotional" ordeal, said police.
The gang also targeted vulnerable home-owners, coercing them into signing over properties to them which were then sold on for profit.
For the convicted gang-members, there were luxurious holidays to Australia, Egypt and Mexico, high-performance BMWs, spa days and cosmetic surgery.
It was a far cry from what Chief Superintendent Nikki Mayo, who led the investigation, described as the "suffering" inflicted on the men they employed.
She said: "The tragedy in this case is that the victims will never get those years of their lives back - we believe one man was held for 26 years.
"The severity and gravity of the charges speak for themselves.
"Modern slavery is a cruel and extremely demoralising crime and it's important that people understand that it isn't just forced labour like this - victims can be sexually exploited, or forced into committing crimes."
She added many of the victims "have now got their lives back".
The gang in full:
John Rooney, 31, of Drinsey Nook, Sheffield Road, Saxilby, Lincolnshire - conspiracy to require a person to perform forced or compulsory labour, conspiracy to defraud, fraud by false representation and two counts of theft.
Patrick Rooney, 31, of Drinsey Nook, Sheffield Road, Saxilby - conspiracy to require a person to perform forced or compulsory labour, fraud by abuse of position, assault occasioning actual bodily harm, and two counts of theft.
Bridget Rooney, 55, of Drinsey Nook, Sheffield Road, Saxilby - conspiracy to require a person to perform forced or compulsory labour.
Martin Rooney, 35, of Sainfoin Farm, Gatemoor Lane, Beaconsfield - conspiracy to defraud, two counts of converting criminal property.
Martin Rooney, 57, of Drinsey Nook, Sheffield Road, Saxilby - conspiracy to require a person to perform forced or compulsory labour and unlawful wounding.
Martin Rooney, 23, of Drinsey Nook, Sheffield Road, Saxilby - conspiracy to require a person to perform forced or compulsory labour and assault occasioning actual bodily harm.
Patrick Rooney, 54, of Sainfoin Farm, Gatemoor Lane, Beaconsfield, Buckinghamshire - converting criminal property.
John Rooney, 53, of Chantry Croft, Pontefract, Yorkshire - two counts of conspiring to require a person to perform forced or compulsory labour.
Peter Doran, 36, of Washingborough Road, Lincoln - conspiracy to require a person to perform forced or compulsory labour.
Gerard Rooney, 46, of Washingborough Road, Lincoln - conspiracy to require a person to perform forced or compulsory labour.
Lawrence Rooney, 47, currently in prison - conspiracy to require a person to perform forced or compulsory labour.