Naidoo v Barton: undue influence and the risks of mutual wills

02 May 2023

Mutual wills are the stuff of legal cautionary tales. These unusual devices typically involve a married couple entering into wills in identical terms, with an agreement that neither party shall alter or revoke their will during their lifetime without the other’s consent, or after the first death. The terms of the will therefore effectively remain binding on the survivor after the first death regardless of whether they make a later will.

However, in Naidoo v Barton [2023] EWHC 500 (Ch), a rare decision relating to the use of mutual wills, the High Court has overturned the surviving spouse’s will on the ground of undue influence.


In 1998, shortly before the death of Dr Naidoo, David Barton, one of Dr and Mrs Naidoo’s seven children, arranged for his parents to draft mutual wills. The wills left the entirety of their estates to the surviving spouse and subsequently to David and his wife.

In 2015, and shortly before her own death, Mrs Naidoo made a new will nominating David’s younger brother, Charan Naidoo, as sole executor and beneficiary.

Following Mrs Naidoo’s death, David challenged the 2015 will on the grounds that the mutual will could not be revoked following Dr Naidoo’s death.

A claim was brought before the High Court in which Charan sought confirmation of the validity of the 2015 will and recission of the 1998 wills on the grounds of mistake on the part of Mrs Naidoo and undue influence by David.

Perhaps relevant to the court’s overall perception of David, much of the trial was conducted via video link as he was serving a sentence for multiple offences, including fraud against vulnerable residents of a care home at which he worked.


Charan claimed that Mrs Naidoo had believed that she could alter her 1998 will following the death of Dr Naidoo, should her intentions have changed by that time. He therefore argued that this will was vitiated on the ground of mistake.

However, the court rejected this, concluding that Mrs Naidoo understood clearly the limitation imposed by the mutual will.

Undue influence

Charan also argued that the will should be rescinded on the ground of undue influence.

Here, the court decided that, where undue influence is claimed to have been used against vulnerable testators to force them to make mutual wills, the appropriate test to use is the equitable doctrine in Royal Bank of Scotland Plc v Etridge (No.2) [2002] 2 AC 773 (which sets out the tests for undue influence in respect of lifetime transactions), rather than the common law doctrine of undue influence in relation to wills (which imposes a more stringent test). This is the case irrespective of whether the mutual agreement is contained within or separate to the will.

Under the principles in Etridge, undue influence is presumed to be exerted in circumstances where the defendant has either applied improper pressure or coercion or has developed a relationship in which a measure of influence has been gained over the other person and this has been used to take an unfair advantage.

Conversely, the common law doctrine of testamentary undue influence sets a far higher evidential burden, requiring actual undue influence through coercion or fraud to be demonstrated for the remedy to apply, something which is notoriously difficult to prove. The more exacting burden, and the steps needed to prove this, was demonstrated in Harrison v Barrett [2023] (Case No: PT-2021-000349). In that case, a daughter successfully proved testamentary undue influence using the transcript from recordings on a camera, installed in the deceased’s home, of conversations between one defendant and the deceased who was, at the time, suffering from dementia. Evidently, this is not an option available for many claimants and the legal issues surrounding obtaining evidence in such a manner can be complex.

In this case, the confidence of Mrs Naidoo in her son’s advice was sufficient for her to instruct for mutual wills to be drafted on the terms that David dictated. The benefit that David received from this decision far outweighed any benefit which Dr and Mrs Naidoo may have gained: “The sole beneficiary of this restriction would be Mr Barton, who would be bound to take the estate of the survivor on death.” Stating that “there is no satisfactory explanation” for the mutual wills on the part of Mrs Naidoo, the court concluded that such drafting could only have resulted from a measure of influence and subsequent unfair advantage taken by David.


In light of the above factors, the court ordered that Mrs Naidoo’s 1998 will be rescinded and the 2015 will be admitted to probate.

Concluding remarks

This decision suggests a pragmatic approach to the remedy of undue influence on the facts of the case. Notably, the Law Commission has recently announced that it is re-commencing its review of the law relating to wills. In particular, one of its recommendations is the introduction of a new statutory doctrine of testamentary undue influence, akin to the Etridge principles, including a presumption of undue influence in certain circumstances. The current decision is perhaps indicative of the practical usefulness of such reform.

Despite the favourable outcome for the claimant, the case serves as another cautionary tale of the risks of mutual wills, the potential restrictions that these place on any future desire to amend one’s will, and the time and costs involved in attempting to unravel such arrangements.