There is a great deal of wisdom in Trainspotting
(the book, much more so than the film) not least in its points about the dangers of leverage. When Renton comes to London he is deeply suspicious at the supposed wealth of those he meets. "Ah've known schemie-junkies in Edinburgh wi a healthier asset-tae-debt ratio then some two-waged, heavily-mortgaged couples doon here," he observes. "It'll hit the fan one day. There are a sack load ay repossession orders in the post."
And so it was to prove. There are now 1.2m people in negative equity, about 10 per cent of all mortgage holders according to modest estimates by Michael Saunders of CitiGroup. If house prices fall another 10% then, staggeringly, a quarter of all mortgage holders will be in negative equity. So, to use Renton's analogy, those junkies in Edinburgh will be financially better-off than about three million British mortgage-holders by about this time next year.