Gordon Brown is thinking about calling an early election. Among the reasons to believe he should do so is the vulnerability of the UK to a housing meltdown similar to that in the US. Since the run on Northern Rock was merely an indirect consequence of US turmoil, what would happen if a crisis were home-grown? Nobody knows. However confident he is about the UK economy, the prime minister might be wise not to wait to find out.

Why might the UK go the way of the US? The answer is that it has very similar vulnerabilities: house prices are high by any standards; in the second quarter of 2007, household saving was only 3.1 per cent of disposable income; as house prices have soared, so has residential investment, which has reached 10 per cent of disposable income, up from just 5.5 per cent six years ago; and the overall household financial deficit is, in consequence, at the record level of 7 per cent of disposable income.