Undue influence is the ground everyone suspects and few can prove. In probate it means coercion: pressure that overpowered the testator's own volition so that the will expresses someone else's wishes. Persuasion, appeals to affection, even relentless lobbying are lawful; the line is crossed where the testator signed for peace, or fear, or because dependence left no practical choice. The challenger must prove it as a fact, there is no presumption in probate merely from relationship, and that burden shapes everything about how these cases run.
The recognisable patterns
The fact patterns recur: an isolated testator, dependent for care, transport or company on the person benefited; access by other family members discouraged or controlled; the beneficiary instructing the solicitor, attending the consultation, holding the will afterwards; a document departing sharply from every earlier testamentary pattern and from expressed intentions. No single feature proves coercion, and courts say so, but the accumulation, dependence plus procurement plus departure plus secrecy, is what successful cases are built from.
The neighbouring grounds
Undue influence rarely travels alone. Want of knowledge and approval, that the testator did not truly know and approve the contents, carries a lighter burden where circumstances excite suspicion, and a will procured by its principal beneficiary must affirmatively satisfy the court's conscience. Capacity overlaps too, since impairment is the soil dependence grows in. Well-pleaded challenges deploy the grounds together, and well-defended estates answer them together, usually on the strength of the drafting solicitor's file.
Practical counsel
For families who suspect: gather what is contemporaneous, who arranged the will, who was present, what the testator said before and after, and take advice before the grant issues, when a caveat still holds the position. For testators who intend an unequal will in circumstances that will look suspicious: make it bomb-proof, independent solicitor, instructions alone, reasons recorded, medical confirmation where age or illness invites doubt. The best answer to a future undue influence claim is a file that shows a free mind at work.
This article is general information, not legal advice. For the full practice area, see Contested Wills and Probate Litigation, or contact the practice to discuss a matter in confidence.