The NatWest Three bankers were each sentenced to 37 months in jail today after pleading guilty to an Enron-related fraud in a deal with US prosecutors.
David Bermingham, Gary Mulgrew and Giles Darby, all 45, were extradited to the US under a controversial treaty 20 months ago and pleaded guilty at the US district court in Houston, Texas, in November.
Judge Ewing Werlein Jr ordered the trio to all serve 37 months behind bars and pay back a total of $7.3m (£3.5m) to the Royal Bank of Scotland, NatWest's owner, when he sentenced them at the US district court in Houston, Texas, today.
In return for the guilty pleas to one count of wire fraud, US prosecutors asked for the six other counts to be dismissed and supported the trio's request to "serve some of the sentence" in the UK.
The three men admitted a conflict of interest and breach of "fiduciary duty" by not informing NatWest that they were considering investing in a company owned by collapsed US energy giant Enron.
They left the bank and bought a stake in the company, Swap Sub, which they then sold on for a huge profit, making around $7.3m dollars (£3.5m) themselves.
Bermingham, of Goring, south Oxfordshire, Glasgow-born Mulgrew, and Darby, of Lower Wraxall, Wiltshire, have all been described as "ordinary family men" and are known to be keen to return home to the UK as soon as possible.
After their guilty pleas last year, assistant attorney general Alice Fisher, of the criminal division of the US Department of Justice, said the trio implemented a "secret and illegal" deal to yield "millions in profits for them personally at the expense of their employer".
They admitted secretly investing with Andrew Fastow, Enron's former chief financial officer, and Michael Kopper, Enron's former managing director of global finance, in Southampton LP.
Fastow created Southampton for the purpose of purchasing a unity called Swap Sub, which the three defendants were selling on behalf of NatWest.
"The three defendants concealed their scheme from NatWest through a series of financial transactions, including the use of options and offshore entities," a US Department of Justice spokesman said.
According to plea documents, in May 2000, within weeks of their investment, Bermingham, Darby and Mulgrew received around 7.3 million dollars (£3.5m) between them.
The three men pleaded guilty to wire fraud and admitted sending an email containing the final Swap Sub sale documents from London to Houston on 17 March, 2000.
Kenneth Kaiser, assistant director of the FBI's criminal investigative division, said the guilty pleas showed "the extent of the fraud at Enron went well beyond US borders".
He said: "The FBI remains committed to bringing to justice those responsible for corporate fraud, no matter where our search may lead."
Kopper, Fastow and others received a total of approximately $12.3m (£6m) for their part in the scheme.
Kopper pleaded guilty to conspiracy and money laundering, and was sentenced to three years and one month in prison.
Fastow was sentenced to six years in prison after pleading guilty to conspiracy to commit securities and wire fraud.