On Thursday at noon the Bank of England’s monetary policy committee will announce its decision on base rates. Suppose I think the rate will stay the same, and the market expects it will rise. At 11am I make a trade that reflects my judgment. I am right, the market is wrong, and I make a profit – perhaps a large one.

The social rationale of financial markets is that they discover information and create liquidity. But the benefit to society of more informed guesses of what the MPC will announce in an hour’s time is small. The benefit of creating liquidity at 11am, when the decision is uncertain, rather than at noon, when it is known, is also small.