Amid the fervour of the hunt for finance heroes it may be easier to spot villains.With the opening of the final act in NAB's demerger of its Clydesdale Bank division in Britain, students of the industry can only reflect on an awful history dating from the 1984 purchase of Clydesdale.A degree of dreamy thinking accompanied the 1989 takeover of Yorkshire Bank, supposedly a portent of great things ahead.NAB then pulled off the star Australian banking survival act in the recession of 1990 and set itself up for misadventure in the US mortgage market.A maddeningly slow appraisal of the risks at HomeSide led NAB into the wilderness of the industry in the early 2000s, setting up a culture of short-serving CEOs.NAB's to do list never changed much from CEO to CEO, so finally tackling Clydesdale is at least a marker of progress.But blimey, what else could NAB have done?Engineered a trade sale or engineered a BS roll up story with value prospects are two possibilities.The lack of a trade sale being the telling detail.This part of NAB Australia's banking business in this market has no value.The greater worry: the people who ran NAB in the past - meaning by and large the people who run NAB today - are the perpetrators of the decay in Clydesdale.Their claims as custodians of domestic banking franchises in Bank of New Zealand and National Australia Bank might be considered tenuous at best.