Much though the mediation group at Three Stone encourages mediation, its members recognise that there are cases where refusal to mediate or engage in some other form of ADR may be justified, and a party may, without fear of costs consequences, simply take the view that they want to press on to vindicate their rights. So the short answer to the question “Must you mediate?” is “No”: not in every case, and there is support for that proposition in recent case law.
Grijns v Grijns and others [2025] EWHC 1413 (Ch) is an example. The case was a dispute about a family property. The details need not concern us. Suffice it to note that one member of the Grijns family, Andrew, brought proceedings claiming a substantial beneficial interest in a family property in Chelsea. The defendants were his mother and brothers. Master Bowles, sitting in retirement, dismissed all his claims and ordered him to pay the defendants’ costs of the substantive claim on an indemnity basis, holding that his claim was unfounded. Andrew’s attempt to argue that the defendants’ approach to mediation should be taken into account when deciding costs was rejected by the master who found that the defendants’ conduct had been reasonable in all the circumstances of the case ([2025] EWHC 2853 (Ch)).
There are several passages in the master’s judgment that repay reading, including his application of the judgment in PGF II SA v OMFS Co Ltd [2014] 1 WLR 1386 to the facts of the case before him. Two stand out. In the first the master said:
“[T]his is not a case where the Defendants ever refused to mediate. In consequence, the question as to whether or not it would have been reasonable for them to refuse mediation is not, in this case directly in point. That said, in a case where, as here there has been no mediation and where the Defendants are said to have been unreasonable in their approach to mediation, the existence, or otherwise, of factors, in the case, that would have justified a refusal to mediate is plainly relevant to the overall reasonableness, or otherwise, of the Defendants’ approach to mediation.”
The second is this:
“In this case, I have no doubt at all that it would have been wholly reasonable for the defendants to refuse to mediate. [Leading counsel for the Defendants] drew my attention to a number of situations, outlined in the ADR Handbook, where courts have determined it to be reasonable for a party not to mediate. Those situations include, at paragraphs 11.13 and 11.21 of the Handbook, the situation where parties face what they properly consider to be an unfounded claim (as Andrew’s claim was) and where, as here, they wish to contest the claim, rather than buy the claimant off. In such cases, as indicated in the ADR Handbook and, as explained in Halsey [v Milton Keynes General NHS Trust [2004] 1 WLR 3002], at paragraph 18, courts customarily are (and rightly should be) unwilling to characterise the conduct of the party who refuses mediation as unreasonable. In this case, as already stated, I would unequivocally take the same view.”
MJS Projects (March) Ltd v RPS Consulting Services Ltd [2026] EWHC 884 (TCC) is another case in which, following the trial of a claim arising out of the design and construction of a container park near Felixstowe Port ([2025] EWHC 831 (TCC)) which the claimant lost, the claimant valiantly argued that there ought to be no order as to costs for two reasons, the first of which was the defendant’s unreasonable failure to mediate.
Giving judgment on costs, HHJ Kelly said:
“The Defendant’s reasoned rejection of one form of ADR, namely mediation, was not unreasonable. The legal issues were clear and largely agreed between the parties. This case would always depend upon the Court’s assessment of the expert evidence. […]
“Even had mediation taken place, I do not accept that it would have had reasonable prospects of success in this case. The Claimant had not engaged with the Defendant’s allegations of poor workmanship nor provided its expert evidence. The Defendant’s reasonable wish to understand the case it was meeting was not just going to disappear. Offers were being made both ways in the run up to trial. The parties remained a vast distance apart.”
She reminded herself:
“A failure to engage in ADR, even if unreasonable, does not automatically result in a costs penalty. It is one of the factors to take into account when exercising the discretion about costs. The question is whether the conduct as a whole is unreasonable. Making and standing by a reasonable offer may not be unreasonable conduct in the light of the ultimate judgment. A refusal to mediate or to accept an offer made when a party is then successful simply means the parties have lost an opportunity to resolve the case without a hearing (see Assensus Ltd v Wirsol Energy Ltd [2025] EWHC 503 (KB) and Northrop Grumman Mission Systems Europe Ltd v BAE Systems (Al Diriyah C41) Ltd [2014] EWHC [2955] (TCC)).”
She went on to make the usual order, namely that the claimant should pay the defendant’s costs, to be assessed if not agreed, saying
“I accept that the Defendant did not agree to the various suggestions for mediation which were proposed by the Claimant. However, I also accept the submission of [leading counsel for the Defendant] that to look at that fact alone is to oversimplify the background to the discussions between the parties in this case.”
There have, of course, been similar cases before, although the majority weigh in very much on the side of mediation; and even the two decisions discussed above are a long way from encouraging parties not to mediate. Both judgments relate to cases in which there was a clear winner and loser, and that was likely to be the case from the outset. That is the exception rather than the rule: most litigation is conducted in the grey area tainted by uncertainty and risk. As Lord Ackner once said, “The corridors of the courts are littered with the debris of unlosable cases that were lost and unwinnable cases that were won.”
That is why mediation needs to be considered in all but the most exceptional cases.
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Stephen Baister specialises in acting as a mediator in insolvency and insolvency-related cases.
If you have any mediation requirements you’d like to discuss, please get in touch with the team.