The 25 years she handed down last Wednesday amounts to a life sentence for a 63-year-old man with heart disease. If Ebbers’s appeal fails, lawyers said he would serve a minimum of 21 years.

After the sentencing, his wife, Kristie Ebbers, rushed into his arms. The couple embraced for several minutes. Both cried softly.

Just three years ago Ebbers was chief executive of global telecoms giant WorldCom and one of the world’s most celebrated executives. Now, having been found guilty of orchestrating one of the largest corporate frauds in history, he faces one of the longest sentences ever meted out to a former chief executive.

Ebbers joins the sentenced-to-jail list of other once- celebrated business leaders: Martha Stewart, Timothy and John Rigas of Adelphia, Enron’s Andrew Fastow and Frank Quattrone of Credit Suisse First Boston.

The excesses of the last stock-market boom have been followed by an exhaustive legal purge. In the Enron probe alone, there have been more than 30 indictments or convictions of top executives.

John Quelch, Harvard Business School professor, said the American economy made cycles of boom and purge almost inevitable.

“America welcomes entrepreneurs but it also lacks the balances to stop things like WorldCom from happening,” he said. “The system requires constant tests or confidence erodes. Credibility requires that the system is challenged.”

This test has given Ebbers its severest response.

The Canadian-born former school janitor and sports coach built WorldCom into a global telecoms giant. The company undercut and outperformed competitors to such an extent that the entire telecoms sector ran into trouble trying to keep up. But its numbers were lies. It collapsed in July 2002 as the biggest bankrupt in US history.

Ebbers claimed he had no knowledge of the $11 billion (£6.27 billion) fraud and that it was committed by underlings without his knowledge.

His defence is similar to the one being used by Ken Lay, former chief executive of Enron. Lay claims he had no knowledge of the financial chicanery that led to the Houston energy firm’s collapse. Like WorldCom, Enron’s fall wiped out billions in savings for pensioners and workers. Unlike Ebbers, Lay sold shares in the company shortly before the collapse.

“Twenty five years is a tough but fair sentence,” said Jacob Zamansky, a lawyer at Zamansky Associates, which has represented shareholders who lost money in the last market collapse.

“It’s a confidence-building measure. These people got away with murder for years. Hopefully, if the Enron crew get convicted, they’ll get similarly tough sentences.”

The sentencing guidelines for white-collar crime were rewritten in the mid-1980s, vastly increasing penalties. They are now often punished as severely as violent crimes. Judges are likely to look at the Ebbers and Rigas sentences when determining how long the next convicted executive should spend behind bars.

“White-collar crime used to be treated like it was a joke, a slap on the wrists and off you go. Well 25 years is no joke,” said Zamansky.

Times Recommends

• Brown targets fat cats after nationalising banks
• US shares soar on global banking rescue
• Europe follows Brown to head off meltdown