A loss is a loss and, by any measure, the loss confirmed by National Australia Bank for the half year to March 2016 is spectacular.?At A$1.74 billion the NAB 2016 half-year loss exceeds the $1.6 billion loss owned up by Westpac in early 1991.Only State Bank of South Australia's loss of more than $3 billion, also in 1991, saves NAB from one dishonourable achievement from decades of mismanagement of its affairs in the UK.The long and compromising history of NAB's custodianship of the Clydesdale Bank, Yorkshire Bank since the late 1980s (and, for a time, two allied banking brands in Ireland) is pretty well understood.The current key leaders of NAB have at least accounted for and resolved the UK legacy as professionally as practicable.No amount of ritual discussion of cash earnings and focus on favourable metrics in the Australian franchise can distract from an iconic moment for an industry on the airbrush.NAB put the total loss from its "discontinued operations" in the UK, completed in early 2016, at $5.1 billion.?The loss from the demerger of its UK banking brands alone NAB put at $4.3 billion, before tax. NAB achieved the demerger by distributing three quarters of CYBG Group shares to NAB shareholders and selling the balance via an IPO.There is also an $801 million charge for "conduct costs" under an indemnity deed, in effect NAB's final cost for its share of the British banking industry's drawn out resolution of the mis-selling of consumer credit insurance.