Banks may have to make yet more provisions for their 27-year-old - and more than 20-year impaired - loans to Bell Group. The company - which became an arm of Alan Bond's business empire - expired at the beginning of 1990s.On Friday, the Court of Appeal in Western Australia ruled that the banks owe even more than the A$1.5 billion slapped on them in a May 2009 ruling.Tony Woodings, liquidator of the Bell Group, estimated on Friday that the effect of the court's ruling would help lift the amount payable to $2 billion, or even $3 billion.       Banks will also have to pay in the order of $250 million in legal costs incurred by the Western Australian State Government over 17 years, as well as most of the bills of the convertible bond-holders that joined the action.Among the 20 banks affected by the ruling are Societe Generale, HSBC, NAB and Westpac.The essence of the 2008 ruling of the Supreme Court of Western Australia, by Neville Owen, was that the banks had pay to the liquidators the money received from selling the Bell assets in 1992, plus interest.That ruling stands on the grounds that the banks knew - even if the Bell directors did not - that at the time Bell was insolvent. This was at the time of refinancing in early 1990.The twist in the appeal court's ruling is that the investors in convertible bonds of Bell Group will now be on an equal footing with other unsecured creditors.This list includes the banks (having lost their status as secured creditors), the Australian Taxation Office, the WA State Government and a myriad of small creditors.Two out of the three judges of the court of appeal - Malcolm Lee and Douglas Drummond -ruled that the investors in the convertible bonds ranked equally with the banks and other unsecured creditors.Bell group directors and Bell group bankers believed the bond-holders ranked equally at the time of the negotiations over refinancing in late 1989 and early 1990, and the banks' efforts to obtain security ahead of the bond-holders was a central controversy in the case.In January 1990, Bell owed the banks around $260 million and the bond-holders around $548 million.For the present generation of bankers, the issue now is how much they have to pay back to the liquidator and then how much of this they will receive back.There are indications that the answer to the former question is along the lines of "more than is provided for".One scrap of evidence regarding the sufficiency of bank provisions was a disclosure by National Australia Bank, in April 2009. NAB said at the time that it took a provision of $65 million this half "with respect to long-standing legal proceedings where settlements are imminent."This was clearly a reference to the Bell case, where the ruling on the value of the banks' liability - which was omitted from the original October 2008 ruling - was about to be brought down.The NAB disclosure was extraordinary at the time, given