In-depth: Deloitte and accounts expert both cleared what HPE described as 'contrived' Autonomy sales

Legal opinion: Ruddy complex, all this expert evidence stuff

Sam Roberts, a senior associate at commercial disputes law firm Cooke Young & Keidan, opined to The Register that hiring expert witnesses doesn’t always make life simpler.

Roberts said: "Instructing experts in commercial litigation is always a minefield of potential pitfalls for the unwary, and a key one is the difficult interplay between disputed factual and expert evidence.

"Claimants have to approach presenting their cases at trial like a construction project: all of the pieces need to fit together, and one bad section will cause the entire structure to crumble."

In the comments section of our last article, some people were wondering why HPE had given such precise assumptions to its expert accounting witness, Peter Holgate.

"What this means in terms of expert evidence is that it will usually have to be presented on the basis that the claimant's factual evidence is accepted by the court. This will (and should) lead claimants to instruct their experts on the basis of assumptions."

Regular readers will recall that is exactly what HPE did.

Roberts continued, using a hypothetical example to illustrate the point: "Take, for example, a case where a claimant alleges some fraudulent bank transfers were used to shuffle funds between various bank accounts, and the claimant instructs a forensic accountant to quantify its loss. The accountant will have to assume that the accounts shouldn’t have received the funds, but if the factual case on fraud falls away in the face of an innocent explanation, the expert’s conclusions can’t stand either."

Neither is it as straightforward as that. Like most legal concepts, there's always a caveat. Two, in Roberts' view: "The first is the famous GIGO principle – garbage in, garbage out. If the assumptions given to the expert don't align with the claimant's factual case, then the expert's evidence is probably worthless. If the court accepts the claimant's factual case, then it will have no relevant expert evidence to go on.

"The second caveat," Roberts explained, speaking in broad-brush terms and not about the Autonomy trial specifically, "is that the assumptions given to or used by the expert should be clear from the expert's written report, and shouldn't be tumbling out at trial. 'Hidden' assumptions can sometimes be used to prop up a bad case, but it is not a good long term strategy."

Pitfalls do exist too. Roberts said: "It's also not uncommon for less experienced experts to make their own unwritten assumptions, which aren't known to the legal team: this risk becomes more acute the more esoteric the subject matter and the less your average lawyer can be expected to understand the technical details of the expert's discipline."

While that may not apply to the Autonomy trial – at £4m per month for both sides, the legal fees alone ought to have bought the tightest possible legal scrutiny of each side's arguments before the trial began – it's a point worth bearing in mind for the legally inclined among El Reg's readership.

Although the Autonomy Trial ended in mid-January, judge Mr Justice Hildyard is still preparing his judgment. The Register expects that to be delivered before May this year, though seasoned legal minds say this would be remarkably fast. This occasional series looking at the in-depth expert accounting evidence, plus the experts' live court testimony, will continue.

At least one man probably wants judgment sooner rather than later; Mike Lynch himself is now the subject of extradition proceedings brought by the American government, and a civil finding in his favour could well be cited as reason not to send him abroad for trial. El Reg is keeping an eye on both cases, with the next extradition hearing due in a few weeks from now. ®