This past week has seen the beginning of a High Court action in London that many in the investment industry hoped would never see the light of day.

But Unilever and Merrill Lynch Investment Management (MLIM) - which was formerly Mercury Asset Management - have failed to settle their differences and now it seems that the dirty laundry in the Unilever pension fund managed by MLIM will be given a full public airing.

Now this is going to be a horrendously complex action but, in simple terms, the row is about MLIM's management of the Unilever pension fund. Unilever pension trustees are suing MLIM for £130 million sterling (€208 million) after the then Mercury Asset Management failed to meet performance targets from January 1997, after the two sides renegotiated their contract to impose a more conservative investment mandate on the pension fund manager.

Unilever is expected to claim that this mandate was not followed, to the extent that the fund lost £130 million. MLIM is expected to claim that the new performance targets were guidelines and not guarantees, and that there was no question of the pension fund being managed in a negligent manner.

If a settlement is not reached - and that now seems likely - then a procession of the City's great and the good will be called to testify.

It promises to be fun, but fund trustees and their fund managers will be watching the outcome with keen interest.