Expert Determination – So What’s New In 2026?
I must declare an interest: I am a keen advocate for expert determination (ED). Why? Because I have been doing them since about 1995, because I was in the first group of 5 to be accredited as an ED by The Academy of Expert (the only professional body to award this accolade), because I am now their chief examiner in ED, but more than anything because I have done dozens of EDs and no one has ever tried to appeal my decisions. When I give a decision, the parties achieve finality to their dispute, which is their main aim.
Mind you, it is difficult to appeal an ED’s decision. Many have tried, but they will only succeed on one of three grounds. Let’s look at them:
Fraud or collusion
This goes back a long way. In the seminal case of Campbell -v- Edwards [1976] 1 WLR 403, dear old Lord Denning explained that the parties had to agree the expert’s decision because they had contracted to do so. But “If there was fraud or collusion, of course, the situation is entirely different. Fraud or collusion unravels everything.”
Fortunately, there have never been any elements of fraud in any of my EDs, so let’s move on.
Failure to follow instructions
This is more prevalent. I give two examples.
In Begum –v- Hossain [2015] EWCA Civ717 the expert (fortunately not an accountant) was instructed to value the 50% of shares in a company operating an Indian restaurant, giving a non-speaking decision (that is, without giving reasons). He gave reasons – not clever. Secondly, he was instructed to take into account not only the official financial records, but also the handwritten records of takings (one set of records for the taxman and the other showing the true position? Disgraceful!) In the reasons which he was instructed not to give, he said he found the handwritten records too difficult, so he ignored them.
Clearly he had not done as he had been instructed to do, and his decision was set aside. The parties would have to start again. Not good.
Then, with a more technical example, we turn to Veba Oil Supply & Trading Gmbh -v- Petrograde Inc [2001] EWCA Civ 1832. This concerned the measurement of the flow of gas in a pipeline across Europe. This had often been measured by a particular brand of flow meter which was now regarded as rather inaccurate, and a new brand was now regularly used. So the expert used the new model.
The court found that the expert was required to use the old model and he had not done so. Result: finding flawed, start again.
Moral: the parties’ advisers must be very careful in drafting their instructions to the expert, and the expert must be very careful to do as he is told.
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Manifest error
Things have moved on since Lord Denning’s day. He said that the parties must accept the expert’s decision even if he is wrong, because they have contracted to do so. No longer. There are several cases where it was found that the decision should not be accepted if there was a manifest error.
Drafting advice: as we now see in many DRCs (Dispute Resolution Clauses), the decision of the expert is final except in the case of fraud or manifest error.
So what is a manifest error?
Turning first to Amey Birmingham Highways Ltd v Birmingham City Council [2018] EWCA Civ 264, the court found that a manifest error was “…an error which is obvious or easily demonstrable without extensive investigation.” And the Veba case helps us further, where Simon Brown LJ said, obiter, that manifest errors are “…oversights and blunders so obvious and obviously capable of affecting the determination as to admit no difference of opinion.”
So there must be oversights and blunders which are very obvious, and which can affect the decision; in other words, which can cause a party to pay more than they should.
So, speaking personally, my view is that the expert must have acted in a particularly stupid way for his/her decision to be overturned.
Let us turn then to two recent cases, which don’t tell us anything new, but which reinforce the decisions already described.
First, WH Holdings Ltd -v- London Stadium LLP [2026] EWCA Civ 153, a case concerning the holding company of the recently-relegated West Ham UFC and the Olympic Park in East London, where they play. The question was whether an additional £3.6 million should be added to the purchase price, and the argument surrounded the difference between “and” and “or”.
Philips LJ said that if he had been asked to decide that in normal litigation he would not have agreed with the expert’s decision, but that was not the test here. The expert may have reached the wrong decision, but it was not a manifest error so the decision stood.
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Now for one which went the other way. In Hamid Nawaz-Khan & Ors -v- UAP Ltd [2026] EWHC 641 (Comm), a share purchase dispute, there were provisions on the liability side of the balance sheet for “Claims Provision” and “Deferred Fee Income”. These were apparently because payment had been received in advance for certain services.
So the cash was already in the bank, but the services had not yet been delivered. The expert treated these as cash deposits, as assets not liabilities. By so doing, he counted the cash twice. As the judge said, he caused the Buyer to pay for fresh air. Impossibly stupid? Read on!
Because that is precisely what happened on one of my cases.
I was approached by a man who had bought a company running an after-school nursery. Parents would prepay the care costs, often a term at a time, and some £100,000 was in the bank. When consulted, I saw immediately that £100,000 was a liability for services which had not yet been provided. The expert struggled with this, had several meetings with my client, and eventually added the £100,000 to the value of the company! As in Hamid, he treated liabilities as assets and caused my client to pay £100,000 for fresh air.
I knew this expert well, so I wrote and asked him to reconsider. He first said it was none of my business, and then that he would not change his opinion. So we were going to court to have his manifest error overturned.
In the event, my client decided to sell his business (this was a branch of a much larger enterprise) and he couldn’t do that with ongoing litigation. So he swallowed the £100,000 – quite unfair.
But none of this quells my enthusiasm for ED with a competent expert. As with litigation, where I have said many times that lawyers must choose their experts carefully, so with expert determination, a fortiori.
