The case was brought by the president of the association set up to defend the interests of former BES customers who were sold the commercial paper, issued by other Espírito Santo group companies - which turned out to be all but worthless when they filed for court protection.

Ricardo Ângelo, the association president, and Rute Sousa, who invested thousands of euros in the commercial paper that they lost when BES was wound up and group went bankrupt, had taken legal action against BES, Novo Banco and Eduardo Stock da Cunha, a former chairman of Novo Banco, with a view to getting their money back.

In the meantime they dropped the proceedings against Stock da Cunha, while the court declared extinct the action against BES because it had gone into liquidation.

As to Novo Banco, the lower-level court had absolved Novo Banco on the grounds, among others, that the Bank of Portugal had transferred responsibility for paying back the money invested in the commercial paper to the 'bad bank', BES, which is now in liquidation and is not expected to have the money to pay these creditors.

Following that decision, Ângelo and Sousa lodged an appeal against it. The appeal court made its decision on 13 July.

In its ruling, the appeal court also said that cases still being considered by the administrative tribunal, which call for actions taken by the Bank of Portugal to be struck down, could be damaging to this case.

“However, it is important to clarify the situation and pave the way for the frank debate that has not taken place here," the judges said in their ruling.

In comments to Lusa, Ângelo said that the ruling is a victory for commercial paper holders and makes finding a solution for them all the more "legitimate".

On Wednesday Portugal's parliament is expected to approve legislation to create credit recovery funds that are to provide a framework for partial compensation for the holders of commercial paper sold by BES, whose investments total some €400 million.

The legislation has been criticised by other associations set up to defence BES victims, who see it as made to measure for the investors in commercial paper, instead of being designed to apply to other situations.