Unjust enrichment and contractual scope: lessons from RMK Maritime (Europe) Ltd v CMB.Tech NV (formerly Euronav NV) [2025] EWHC 2739 (Comm)

The decision demonstrates that a claim for unjust enrichment cannot be used to circumvent a contract that allocates the risk of additional work and prescribes how changes to scope and remuneration must be agreed. A party seeking payment for work said to fall outside the contractual scope must address that contractual machinery and establish a recognised unjust factor.

Overview of unjust enrichment

A claim for unjust enrichment is made where one party is enriched at the expense of another party in circumstances which the law recognises as unjust.

The law of unjust enrichment generally responds by requiring the defendant to reverse an enrichment received at the claimant’s expense in circumstances recognised by law as unjust. The remedy is measured by the defendant’s gain rather than by the claimant’s loss.

There are four questions that the court will consider when a claim for unjust enrichment is made:

1. Has the defendant been enriched?
2. Was the enrichment at the expense of the claimant?
3. Was the enrichment unjust?
4. Are there any defences available to the defendant?

The burden is on the claimant to satisfy the court of the first three elements. Where the claimant can satisfy the court on the first three questions, the burden then reverses to the defendant to demonstrate that a defence is available.

In answering question 1, a party can be considered to have been enriched where they receive something which a reasonable person would consider to be of value. Enrichment can take both monetary and non-monetary forms. Non-monetary forms of enrichment include goods, land, services and the discharge of a liability.

The second question is whether the defendant’s enrichment was obtained at the claimant’s expense. This requires a sufficient connection between the claimant’s loss of value and the defendant’s gain; it is not enough merely to show that the claimant suffered an economic loss while the defendant was enriched.

Thirdly, the claimant must demonstrate that the enrichment was unjust. The court does not consider whether the defendant’s enrichment was “unjust” in a general sense. There are a number of “unjust factors” recognised by English law that mainly concern circumstances in which the claimant did not intend the defendant to have the benefit. Examples of these “unjust factors” include:

• Mistake: where the claimant transfers the benefit to the defendant because of a mistake, in either fact or law.
• Failure of basis: where the claimant transfers the benefit to the defendant on a shared basis and that basis subsequently fails.
• Duress: where the claimant transfers the benefit to the defendant due to illegitimate pressure put on the claimant by the defendant.
• Undue influence: where the claimant transfers the benefit to the defendant whilst unable to exercise free and independent judgment.

In an appropriate case, the defendant’s knowing acceptance of services supplied in the expectation of payment may be relevant to whether restitutionary liability arises. However, free acceptance does not operate as a general, self-standing unjust factor and the contractual context remains critical.

Where the claimant establishes the first three elements, the defendant may rely on a recognised defence, including change of position or estoppel. A claim may also be defeated if it is brought outside the applicable limitation period.

Remedies for unjust enrichment

The usual remedy for unjust enrichment is a personal monetary award measured by the value of the defendant’s enrichment, subject to any applicable defence. Its object is to reverse the enrichment rather than to compensate the claimant for loss or necessarily restore both parties to their pre-transfer positions.

In limited circumstances, a claimant may establish a proprietary restitutionary remedy, but such relief is not available merely because unjust enrichment is proved. Its availability depends on the claimant establishing an existing proprietary basis for the claim and remains subject to applicable priority rules and third-party defences.

The principles summarised above should be read alongside the authorities on the four-stage analysis, recognised unjust factors, contractual allocation of risk and the applicable limitation provisions.

RMK Maritime (Europe) Ltd v CMB.Tech NV (formerly Euronav NV) [2025] EWHC 2739 (Comm)

In this case, the Commercial Court considered a restitutionary claim arising from mergers and acquisitions advisory work which the claimants alleged fell outside the scope of a written advisory agreement.

Background

The first claimant was a company providing advisory and capital-raising services. The second claimant was affiliated with the first claimant. Both claimants operated under the name “RMK Maritime”.

The claim was for $11,677,600. The written advisory agreement provided for fees totalling $2m.

The defendant was a large crude oil tanker operator that engaged the first claimant in relation to a proposed acquisition. The first claimant’s services were governed by an advisory agreement. The claimants alleged that services provided under the RMK Maritime name went beyond the scope of work agreed in that advisory agreement.

The claimants contended that the agreement required only the development of a model to examine a possible acquisition, whereas they had ultimately provided a broader range of advisory services, including deal structuring, negotiation support and due diligence co-ordination.

The claimants alleged that the defendant had been unjustly enriched by receiving services outside of the scope of the advisory agreement, and asserted that there was a mutual understanding between the parties that the defendant would pay a further fee for the services provided outside of the agreed scope of work. The defendant’s position was that no such mutual understanding existed, and that any additional payment made to the claimants would be in the form of a discretionary bonus.

The claimants asserted that the unjust factors of “failure of basis” and/or “free acceptance” were applicable, making the circumstances in which the defendant was enriched by the claimants unjust. The claimants asserted “failure of basis” in that the basis for the claimants to provide additional services, outside of the agreed scope of work, had failed. The claimants maintained that “free acceptance” applied in that the defendant freely accepted the benefit of additional services with knowledge that the claimants expected to be remunerated.

The defendant maintained that all services provided by the claimants were included within the agreed scope of work. The defendant asserted that there was no common understanding between the parties that the defendant would pay the claimants for services that fell outside the agreed scope of work. Rather, the defendant’s position was that any suggestion of further payment was understood to be at the defendant’s discretion.

Decision

The court dismissed the claimants’ claim in its entirety.

The court found that all work carried out by the claimants fell within the scope of the advisory agreement. It therefore rejected the factual premise that services had been provided outside the agreed scope, before addressing, in the alternative, whether a restitutionary claim could have succeeded had additional services been provided.

In construing the advisory agreement as a whole and applying commercial common sense, the court held that references to RMK supporting the “Project” concerned the entire acquisition process rather than only the initial modelling exercise. Most of the agreed payments were triggered by events occurring after that modelling, indicating a continuing role throughout the transaction. A catch-all obligation to provide other advisory-related work appropriate for the project was also sufficiently broad to encompass all the services performed.

The court found that, even if the claimants had provided services outside the agreed scope of work, there was no sufficient basis in law for the restitutionary claim. It rejected the submission that unjust enrichment is always available unless expressly excluded by contract. The agreement required any change to the scope of work to be agreed in writing and thereby allocated the risk of unremunerated additional work: the claimants could not assert that additional services had been provided, or that further payment was due, unless those matters had been agreed in writing. No such written agreement was made.

The court found that the drafting and wider facts did not establish the shared understanding required for the claimants’ failure of basis case. The defendant had never accepted that the claimants were working beyond the contractual scope or that they would be entitled to additional payment. The court also rejected the alternative free acceptance argument: by providing allegedly additional services without negotiating a written alteration to the contractual scope, the claimants took the risk that those services would remain unremunerated except through any discretionary bonus from the defendant.

Takeaways

The complete dismissal of the claim underscores the importance of aligning contractual drafting with day-to-day project management. Parties should define the original scope of services clearly, specify how variations must be agreed and documented, and ensure that communications about additional work or discretionary payments do not undermine that contractual machinery.

The decision confirms that, on the terms of this agreement, a restitutionary claim could not be used to bypass the contractual mechanism that allocated the risk of additional work and governed changes to the scope of services and entitlement to further remuneration. Where a contract requires written agreement before its scope is enlarged, the absence of that agreement may prevent a restitutionary claim even if services were provided beyond the original scope.

A party seeking additional remuneration should identify the allegedly out-of-scope services, notify the counterparty before undertaking them and comply with the contractual procedure for agreeing changes to scope and payment. Where the contract requires written agreement, contemporaneous communications should record both the expanded scope and the agreed basis of remuneration. Evidence merely showing that services were performed, without the required contractual agreement or a shared understanding that the work fell outside scope and attracted additional payment, may be insufficient.