A Swiss court handed jail sentences to four members of Britain's richest family on Friday for exploiting Indian staff at their Geneva mansion.

The Hindujas -- who were not present in court -- were acquitted of human trafficking, but convicted on other charges in a stunning verdict for the family whose fortune is estimated at 37 billion pounds ($47 billion).

Prakash Hinduja and his wife Kamal Hinduja each got four years and six months, while their son Ajay and his wife Namrata received four-year terms, the presiding judge in Geneva ruled.

The cases stem from the family's practice of bringing servants from their native India and included accusations of confiscating their passports once they were flown to Switzerland.

Prosecutors argued the Hindujas paid their staff a pittance and gave them little freedom to leave the house.

The family denied the allegations, claiming the prosecutors wanted to "do in the Hindujas".

The Hindujas reached a confidential out-of-court settlement with the three employees who made the accusations against them.

Despite this, the prosecution decided to pursue the case due to the gravity of the charges.

Geneva prosecutor Yves Bertossa had requested a custodial sentence of five and a half years against Prakash and Kamal Hinduja.

Aged 78 and 75 respectively, both had been absent since the start of the trial for health reasons.

In his closing address, the prosecutor accused the family of abusing the "asymmetrical situation" between a powerful employer and a vulnerable employee to save money.

Household staff were paid salaries between 220 and 400 francs ($250-450) a month, far below what they could expect to earn in Switzerland.

"They're profiting from the misery of the world," Bertossa told the court.

'Not Mistreated Slaves'
But the Hinduja family's defence lawyers argued that the three plaintiffs received ample benefits, were not kept in isolation and were free to leave the villa.

"We are not dealing with mistreated slaves," Nicolas Jeandin told the court.

Indeed, the employees "were grateful to the Hindujas for offering them a better life", his fellow lawyer Robert Assael argued.

Representing Ajay Hinduja, lawyer Yael Hayat had slammed the "excessive" indictment, arguing the trial should be a question of "justice, not social justice".

Namrata Hinduja's lawyer Romain Jordan also pleaded for acquittal, claiming the prosecutors were aiming to make an example of the family.

He argued the prosecution had failed to mention payments made to staff on top of their cash salaries.

"No employee was cheated out of his or her salary," Assael added.

Some staff even asked for raises, which they received.

With interests in oil and gas, banking and healthcare, the Hinduja Group is present in 38 countries and employs around 200,000 people.

Prakash Hinduja, who obtained Swiss citizenship in 2000, is also facing a separate tax case brought by Swiss authorities.