Endesa, Spain's largest electricity group, is set to appeal against the European Commission's decision to defer to competition authorities in Madrid over rival Gas Natural's controversial €22.5bn ($26.3bn) takeover bid.

Rafael Miranda, chief executive of Endesa, said yesterday he would take the case to the Court of First Instance in Luxembourg, and attempt to convince officials that the proposed takeover warranted the attention of European Union's competition authorities. "This is not a normal deal," he said. "It's a hostile bid by an inferior company paid for in paper and cash taken directly out of Endesa.