Jérôme Kerviel, the trader blamed for a €5 billion (£3.7 billion) fraud at Société Générale, has said through his lawyer that he is prepared to talk with the police if asked.

Elisabeth Meyer said late last night that her client, Mr Kerviel, was "not on the run”.

She also confirmed that he would talk to the police, if asked.

The Paris prosecutor’s office has opened a preliminary investigation into the scandal, and scores of shareholders have begun legal proceedings against the bank for fraud and misconduct.

Meanwhile, President Sarkozy, speaking in India this morning, moved to shore up France's reputation in the financial world, saying that the rogue trader scandal at Société Générale did not affect the “solidity and reliability of France’s financial system”.

“This was internal fraud ... which does not affect the solidity and reliability of France’s financial system,” Mr Sarkozy said in a news conference in Delhi.

The Bank of France, also keen to reassure investors, has assessed SocGen's wellbeing and pronounced it "perfectly healthy" and "solid".

However, a question mark was placed over the future of the second-biggest French bank, the day after the fraud was revealed, as analysts questioned how long SocGen could remain independent.

Bankers and analysts said that the crisis could push SocGen into the arms of BNP Paribas, its spurned suitor and arch rival.

SocGen took out full-page advertisements in leading French newspapers this morning to apologise to Société Générale shareholders.

Daniel Bouton, the SocGen chairman and chief executive, wrote: "I understand perfectly your disappointment and see your anger. This situation is completely unacceptable.

“I ask you to accept my apologies and my profound regrets.”

French newspapers made for uncomfortable reading for SocGen's board if it hopes to emerge unscathed from the scandal.

Les Echos, the main business daily, called the fraud "the shock which stupefied the financial world" and argued that Mr Bouton's position had been weakened and that the bank — the seventh-largest in Europe by value — was now a potential takeover target.

BNP Paribas estimated that SocGen’s trade exposure had been on the order of €33 billion, and others questioned whether the trader was being used as an excuse to hide wider problems at the bank linked to the credit crisis.

Alain Crouzat, portfolio manager at Montsegur Finance in Paris, told Le Parisien newspaper in an interview: "For me, as for others, this 'mad' trader looks more like a scapegoat in this period of financial turbulence."

The stunning disclosure of fraud has at least damaged SocGen's credibility as an award-winning specialist in complex equity derivatives.

In recognition that the supervision of the trader’s books had gone wrong, SocGen said that his immediate bosses had left the company.

Global investors largely shrugged off the scandal.

Asian stocks surged in the wake of a higher close on Wall Street after President Bush and congressional leaders agreed on an economic stimulus package to stave off a recession.

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