BIG four accountancy firm Ernst & Young has claimed that troubled insurer Equitable Life is pouring money down the drain by pursuing a High Court action which is due to begin later today.

Equitable is seeking pounds-2bn damages from its former auditor, claiming it was negligent in the late 1990s when the insurer made promises to policyholders it was unable to meet, leaving it with a huge compensation bill.

The claim, which is also against former directors, is the largest yet to be brought against an auditor in the UK and sets a precedent by targeting nonexecutive directors as well as their executive counterparts.

During the build-up to the start of court proceedings, both Equitable and Ernst have engaged in a phoney war, with each predicting victory. They have also warned the case could cost them pounds-30m or more each, while the reputations of some of the City's biggest hitters are also at stake.

Equitable claims its auditors and directors should have highlighted its vulnerability from so-called guaranteed annuity rates sooner. While claiming it has a very strong case, Equitable has refused to rule out a settlement, simply saying that any offer would have to be "serious and substantial".

In 2000, the insurer closed its life fund to new business after the House of Lords, the UK's highest court, ordered it to honour guarantees on policies sold during the 1970s and 1980s.

The move pushed Equitable to the brink of bankruptcy as it tried to recoup pounds-1.5bn by halting terminal bonuses and shunning new policyholders.

Besides the case against Ernst, Equitable is suing 15 of its former directors for up to pounds-1.7bn in a trial expected to last for up to nine months. The proceedings could cost more than pounds-80m, and involve at least 10 law firms and 12 expert witnesses.

Nick Land, chairman of Ernst, said: "Today sees the beginning of a case that should never have been brought. Nothing that Ernst & Young did caused Equitable's problems. There is nothing we could have told them that they did not already know. There was no black hole, no fraud and no money lost."