Trichet has been preparing to head the ECB for six years

Mr Trichet is the anointed successor to current European Central Bank President Wim Duisenberg, who is set to step down on 9 July.

But that could all change at around 1130 GMT if judge Olivier Perusset rules that Mr Trichet is guilty of complicity in allegedly hiding losses at then state-owned bank Credit Lyonnais in the early 1990s.

A guilty verdict would make it very difficult for him to take over from Mr Duisenberg, who controls the eurozone's monetary policy.

Coverup?

Mr Trichet, 60, is one of nine men on trial for their part in the Credit Lyonnais fiasco, which culminated in a 31bn-euro ($33.7bn) bailout by the government.

One of France's biggest banks, Credit Lyonnais ran into serious trouble following a series of disastrous investments in the late 1980s and early 1990s.

In 1992 and the first half of 1993, the bank's financial situation was so dire that its very solvency was in doubt.

Official accounts signed off by Mr Trichet, however, did not reflect this.

'Plan B'

Mr Trichet says he was deceived by Credit Lyonnais, and was never part of a cover-up.

Under a deal struck by French President Jacques Chirac and other EU leaders at a stormy summit in 1998, Mr Trichet was chosen to replace Mr Duisenberg - who plans to stand down next month.

Few doubt that the Bank of France governor is qualified for the job of ECB president.

He is a highly-respected central banker who oversaw France's strong franc policy in the 1990s.

But in the event of the nightmare scenario - a guilty verdict - there are few candidates ready to fill Mr Duisenberg's shoes.

"The big dilemma is who else would be possible," said Rainer Guntermann of Dresdner Kleinwort Benson.