It did for John Major, just as earlier devaluations had done for prime ministerial predecessors such as Harold Wilson, who had also made a virility symbol out of the currency. But the pound's plummeting on what became known as Black Wednesday, 20 years ago, proved to be a gift in disguise. Memories fix on chancellor Norman Lamont's ill-advised confession that the event left him singing in the bath, on snaps of the young special adviser at his side, which gave Britain its first glimpse of David Cameron, and on reports about billions being lost in doomed trading attempts to salvage sterling. But those billions were trivial next to the sudden flexibility to slash interest rates, and the terrific boost that industry got when products priced in pounds suddenly became bargains in Deutschmarks or dollars. If only the eurozone's stricken south had the freedom to answer today's"black swan" events with a Black Wednesday of its own.. Tomorrow's Guardian editorial.