Non-assignment clauses and the transfer of rights to arbitrate

There is no presumption in English law that transfers of rights by operation of law are exempt from contractual clauses prohibiting the assignment of rights. The important recent case of Dassault Aviation SA v Mitsui Sumitomo Insurance Co Ltd [2022] EWHC 3287 (Comm) established that the relevant distinction is whether the transfer of rights is truly voluntary or involuntary.

A transfer that is given effect by operation of law may be the culmination of a series of purely voluntary acts within the control of the assignor. In such cases, the transfer may have the “taint of voluntariness” and may be caught by a non-assignment clause and invalidated. For those reasons, the Commercial Court held that Mitsui Insurance Co (Mitsui) had not acquired the right to bring an arbitration claim under a contract between its insured Mitsui Butsan Aerospace (MBA) and Dassault Aviation (Dassault).


Dassault contracted to manufacture two aircraft for MBA (the Sale Contract) for onward supply by MBA to the Japanese Coast Guard. The Sale Contract was governed by English law and contained an ICC arbitration clause in which London was the seat of arbitration. It also contained confidentiality provisions and a clause prohibiting the assignment or transfer of any right or interest under the contract “in whole or in part by any Party to any third party, for any reason whatsoever” without prior written consent (the ‘Non-Assignment Clause’). Two years into the contract, MBA became concerned about delays in manufacture and obtained insurance from Mitsui against its potential liability to the Japanese Coast Guard. The insurance policy was governed by the Japanese Insurance Law (JLA). Article 25 of the JLA provides that, once it has indemnified a loss, an insurer is subrogated “by operation of law” to the insured’s recovery claim against any third party. The JLA permits parties to contract out of Article 25, but MBA’s policy with Mitsui in fact contained a clause which had the same effect as Article 25, by providing for the transfer of claims to Mitsui following payment of any loss.

Dassault delivered the aircraft late and Mitsui indemnified MBA under the insurance policy. Mitsui then commenced ICC arbitration proceedings against Dassault on the basis that MBA’s rights under the Sale Contract had been transferred to the insurer. The ICC panel made a partial award that, because the transfer to Mitsui occurred by operation of law, it was not invalidated by the Non-Assignment Clause so that accordingly the panel had jurisdiction to hear the claim. Dassault applied to the English Commercial Court to set aside the award.

The court’s decision

The court’s task was to construe the Non-Assignment Clause and apply it to the disputed transfer of rights to Mitsui. The court accepted that Article 25 of the JLA worked by transferring rights to an insurer by operation of law. By contrast, subrogation under English insurance law requires the claim to be brought in the insured’s name and is not thought to involve any transfer of rights (although there is a lack of certainty about the correct analysis, as the court acknowledged here).

The court began by rejecting Mitsui’s primary argument that there is a rule of English law that transfers of rights ‘by operation of law’ escape contractual prohibitions on assignment. The court found no such broad principle in the case law: the test does not focus on the immediate cause or legal mechanism of the disputed transfer, but rather whether it was truly voluntary or non-voluntary, in the sense of occurring contrary to the will of the transferring party and truly outside their voluntary control. Here, MBA chose to enter into the insurance policy, chose not to contract out of Article 25 of the JLA and chose to claim an indemnity from Mitsui.

The court then construed the Non-Assignment Clause by reference to the words used, the factual matrix and commercial purpose of the Sales Contract, and commercial common sense. The court found that the clear broad words of the clause supported a preliminary conclusion that it applied to the transfer to Mitsui.  The court accepted Mitsui’s argument that the fact that the Non-Assignment Clause might not prohibit a subrogated claim by an English insurer (because it would not involve a transfer of rights), was part of the relevant factual matrix.  However, the court found that there were reasons why contracting parties might treat subrogation differently and that a general prohibition on transfers of contractual rights to insurers would fit with the commercial purpose of the Non-Assignment Clause.  The court concluded that no element of factual matrix/commercial purpose or public policy displaced the initial interpretation based on the words of the Non-Assignment Clause and held that it applied to invalidate the transfer of the right to arbitrate to Mitsui. Accordingly, the court set aside the ICC award on the grounds that the ICC did not have jurisdiction to hear Mitsui’s claim.


This decision will be of obvious interest to insurers and their advisers. Insurers’ rights to pursue recovery claims under their insureds’ contracts with third parties may no longer escape non-assignment clauses simply on the basis that insurers acquire those rights ‘by operation of law’ once they have indemnified the insured. Each case will turn on the specific words of the policy and the non-assignment clause in the underlying contract. The courts may now regard the more important factor as being the insured’s decision to enter into the policy and claim an indemnity, which may colour the transfer to insurers as ‘voluntary’ and potentially bring it within a non-assignment clause. The focus will then shift to the legal basis of the insurers’ right to bring a claim.

For insurers writing policies under systems of law where their title to bring a claim is acquired by means of a transfer of the insured’s rights (as with Japanese law in this case and in contrast to the English law of subrogation), those transfers may be caught by non-assignment clauses and invalidated. Indeed, the judgment leaves open the possibility that English law subrogation claims may one day be caught by non-assignment clauses if the classification problems with subrogation law are resolved in favour of an analysis of transfer of rights. Insurers are therefore now likely to insist that non-assignment clauses in the English law contracts which they insure have express carve-outs permitting transfers of rights to insurers.

The court acknowledged the dispute raised complex issues and that the decision had been reached “with an unusual degree of hesitation”. It will be interesting to see how the case law on this important issue develops.

This analysis was co-authored by Jeremy Collins and first published on Lexis®PSL on 21 February 2023 and can be found here (subscription required). 

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