The news this week that Eric Schneiderman, the New York attorney-general has launched yet another inquiry in Wall Street’s role in the mortgage crisis will no doubt be greeted with groans at investment banks. Four years – and multiple investigations – after the meltdown started at two Bear Stearns hedge funds, isn’t it time to move on?

I think not, for there is still work to be done. With the exceptions of Bernard Madoff and Raj Rajaratnam, no senior Wall Street executive has faced criminal charges, although some in the industry – whether at the top or in the middle – probably broke the law. Such criminality may be hard to pin down after all this time, but it is worth the effort.

There is an element of grandstanding in Mr Schneiderman’s foray – Eliot Spitzer, the former New York attorney-general, parlayed his crackdown after the internet bubble into becoming governor (before his downfall). Wall Street remains unpopular after the bail-out and politicians see opportunity there.