Simon English: Show us what went wrong with Pru's bid for AIA

A trip down the memory hole. About a year ago it was reported that the Financial Services Authority had ordered an investigation into the Prudential's collapsed $35bn (£22.3bn) bid for Asian life insurer AIA. The regulator told Prudential to pay legal eagles Clifford Chance to do some digging, to see what went wrong, who was to blame and if the rules should change.

It is one of those matters on which, as they say, none of the involved parties would comment, but it seemed that the FSA was concerned that the Pru's investment banking advisers Credit Suisse, JPMorgan and HSBC may not have behaved in a manner entirely becoming.

Regulators call this a section 166. Skirts are lifted, probes are made, and that's the most we ever hear.

Now, the Pru is not Royal Bank of Scotland. Despite the utter shambles that the AIA bid quickly became, the Pru was, and remains, a beacon of financial strength.

It was having a good crisis, until chief executive Tidjane Thiam had a rush of blood to the head and decided it was a good time to buy overseas assets of uncertain value.

Mr Thiam survived the fallout; this blip aside, the common view is that he is brilliant.

Still, there is surely a case for this 166 being made public. City folk say the FSA does so many of these inquiries that making them all public would make it impossible for bankers and their clients to function.

That may be self serving, but you can see the point. Still, the Pru is of such importance – millions of us are shareholders, policyholders or both – that perhaps an exception should be made in this instance.

We should not easily forget what a bungle this was. It cost investors £377m. That's an extraordinary amount of money even for the Pru.

Why didn't the company know that the FSA thought it had insufficient capital?

What was the chairman Harvey McGrath (soon moving on) doing all this time?

Were the bankers blinded by the fees into doing insufficient due diligence? Did any of the directors challenge Mr Thiam on this deal?

What about Michael McLintock, the boss of the fund management arm M&G? It somehow seems unlikely that he thought buying AIA was a good plan. The FSA clearly thinks the Pru or its advisers had some serious issues. What were they?

If the matter goes as far as enforcement action – fines and slapped wrists – we get to see at least some of what was uncovered.

We should this time in any case. There has never been a better time for City practices, for the minutiae of gigantic takeover deals, to be scrutinised in the public glare.