The ghost of Enron is taking time to lay to rest. Andrew Fastow’s declaration that leading investment banks helped the bankrupt energy group falsify its books gave the likes of Merrill Lynch, Credit Suisse and Royal Bank of Scotland another day of squirming in the spotlight. They are among the group still facing a $35bn class action lawsuit over the bankruptcy. Will Mr Fastow’s intervention make a difference?

It is obviously not helpful for the banks. He, of all people, knows where the bodies were buried at Enron and can put any incriminating e-mails and other evidence in context. But it is not clear how much new information there was in his declaration. And there will be questions about his credibility as a witness, given that his overall co-operation helped secure some leniency in his sentencing.

Since Canadian Imperial Bank of Commerce settled for $2.4bn a year ago, taking the total in settlements to around $7bn, the wind has appeared to blow in the remaining banks’ favour. Barclays and Deutsche Bank have extricated themselves (at least for the time being). And the judge’s thinking on the key issue of whether any of the banks’ conduct could constitute a “primary violation” rather than “aiding and abetting” Enron has also appeared to shift in the banks’ favour. In a private civil case, they need to be “primary violators” to be found liable.

The banks are probably not sweating as profusely as they were a year ago. And each of the remaining defendants retains the hope that the case against them will be dismissed in a pending motion. But, if not, the heat will be on again. However confident of their legal cases, the banks would need nerves of steel to face trial in front of an unpredictable Houston jury rather than trying to settle.