What is the burden of undue influence against a volunteer who was found to have exercised undue influence on the condition of the volunteer?

I note that the brothers who are presumed to have exercised the influence are not, themselves, the beneficiaries. Volunteers are not, however, entitled to retain the benefits of undue influence; Huguenin v. Baseley [1803-13] All E.R. Rep. 1 at p.9. The respondent does not suggest that they need be parties. I should reiterate that my conclusion does not establish that the brothers were guilty of the actual exercise of undue influence; the presumption exists as a matter of policy to prevent abuse of a relationship. That policy applies with particular force to a situation in which trust and confidence is imposed by a person who is under a disability. I do not say that in this case the burden is any higher than in other cases, I merely say that the burden which the law imposes is justified.