If only. Lawrence McDonald begins his insider's account of the fall of Lehman Brothers with seven “what if” scenarios, speculating on how different decisions might have saved his former employer. If only Dick Fuld, Lehman's chief executive, had listened to those who warned of impending losses on the bank's property portfolio. If only Fuld had not antagonised Hank Paulson, the then Treasury secretary. And so on.*

Mr McDonald is far from the only person who believes that the Lehman bankruptcy could have been avoided. Alan Blinder, the former Federal Reserve vice-chairman, has called the decision to let the bank fail “a colossal error”. Christine Lagarde, the French finance minister, denounced it as a “horrendous” mistake. When an event is followed by such upheaval – the biggest financial panic since 1931, the worst recession since the war – it is only human to imagine how the milk might not have been spilt. When, at January's World Economic Forum in Davos, I argued that this was wishful non-thinking, I found few supporters.

If only. If only Lehman had been saved, there would have been no credit crunch. No near-Depression. The S&P 500 would not have sunk to 682 (its nadir last March). We would probably be back to 1500 by now.