Banks v Goodfellow (1870), Cockburn CJ: As to the testators capacity, he must, in the language of the law, have a sound and disposing mind and memory.

In other words, he ought to be capable of making his will with an understanding of the nature of the business in which he is engaged, a recollection of the property he means to dispose of, of the persons who are the objects of his bounty, and the manner in which it is to be distributed between them.

It is not necessary that he should view his will with the eye of a lawyer, and comprehend its provisions in their legal form.

It is sufficient if he has such a mind and memory as will enable him to understand the elements of which it is composed, and the disposition of his property in its simple forms.

In deciding upon the capacity of the testator to make his will, it is the soundness of the mind, and not the particular state of the bodily health, that is to be attended to; the latter may be in a state of extreme imbecility, and yet he may possess sufficient understanding to direct how his property shall be disposed of; his capacity may be perfect to dispose of his property by will, and yet very inadequate to the management of other business, as, for instance, to make contracts for the purchase or sale of property.Waters v Waters (1848), Coleridge J stated that a specific and accurate knowledge of every atom of his property was not required of the testator but he ought to know generally the state of his property and what it consists of . This will be proportional to the amount of property the testator owns.Harwood v Baker (1840), testator visited the Bank of England a few days prior to his death. He then executed a will in which he left all his property to his wife. Some relatives were left out. The will was invalid. It was held that the testator was too ill to give sufficient consideration to the potential claims of his relatives. Erskine J held : that the question before the court was whether the testator was capable of recollecting who were his relatives, of understanding their respective claims upon his regard and bounty, and of deliberately forming an intelligent purpose of excluding them from any share of his property.

Boughton v Knight (1873), Hannen J stated that apart from the need to recall fitting objects of the testators bounty, a testator had to have an understanding to comprehend their relationship to himself and their claim upon him.Wood v Smith (1992), testator was 82, made a will two days before death. There was evidence that the testator was confused and incoherent. The courts held that there was insufficinet evidence that the testator was able to comprehend the extent of his property or the nature of the claims of those he was excludingBrown v Pourau (1995), though the testatrix was occasionally subject to trances in which she talked to spirits and fairies because she believed a Maori curse had been placed on her, her will was still valid.Estate of Park, testator was 78 and had suffered two strokes. Was also unable to look after his financial affairs. Was previously a successful businessman but became forgetful and confused. He decided to marry a cashier at the club whom he hardly knew. They got married and the testator executed a new will at the reception following the wedding. He died a few days later. The will was a complicated will, It was held that thought he marriage was valid, the will was not on the grounds of lack of mental capacity. The courts drew distinction between simple & complicated wills & implied that mental competence required would differ accordingly.Hannen J in Boughton v Knight : the law does not say that a man is incapacitated from making a will if he proposes to make a disposition of his property moved by capricious, frivolous, mean or even bad motives.

Knight Bruce VC in Bird v Luckie (1850) : no man is bound to make a will in such a manner as to deserve approbation from the prudent, the wise, or the good. A testator is permitted to be capricious and improvident, and is, moreover, at liberty to conceal the circumstances and the motives by which he had been actuated in his dispositions. Many a testamentary provision may seem to the world arbitrary, capricious and eccentric, for which the testator, if he could be heard, might be able to answer most satisfactorily.Dew v Clark (1826), testator gave his only child a small gift out of his large estate. He treated her with great cruelty in her youth and described her as a fiend, a monster Satans special property and a very devil. Evidence however showed that she was of exemplary character. Will was invalid since it was influenced by testators delusion.Waring v Waring (1848) : testatrix suffered various delusion the most interesting being that the PM used to visit her house, disguised as a fish pedlar, in order to have an improper connection with her.Smee v Smee (1879) testator believed that he was the son of King George the IV and his father had defrauded him by preventing him from benefiting from a trust fund which was diverted to favour his brothers. His will totally excluded his brothers. Hannen J directed the jury to find against a will unless your minds are satisfied that there is no reasonable connection between the delusion and the bequests in the will.Re Nightingale (1974) Testator, dying from cancer, cut out his adopted son who was the principal beneficiary under his will, from his second will. Courts held that the testator probably thought that the son was trying to murder him because the son had gently pushed him back onto the bed when he tried getting up.Battan Singh v Amirchand, instructions given to lay intermediaries to be passed to solicitors were held to be invalid.

Smith v Tebbitt (1867) Testatrix left bulk of her estate to a Dr. Smith. Her sister got a small portion. Testatrix believed that she was part of the Holy Trinity. She was the Holy Ghost and Dr. Smith was the Father. She also believed that she would give birth to the Saviour, that she was the Bride of Christ and Virgin Mary and that she would possess Buckingham Palace and Windsor Castle. She also believed that the final judgment would take place in her drawing room and that Dr Smith had resurrected her. Her sister was a child of the devil. Her will was held invalid.Banks v Goodfellow, testator left most of his estate to his niece. She had cared for him and stayed with him. He was once confined to a lunatic asylum. He was still suffering from two delusion i.e. he was being pursued by devils and evil spirits, and, that a man long dead still pursued and molested him. He was however capable of managing his affairs. His will was valid. Cockburn CJ stated : a degree or form of soundness which neither disturbs the exercise of the faculties necessary for such an act, nor is capable of influencing the result, ought not to take away the power of making a will.The Estate of Walker (1912), testatrix was declared a lunatic. She suffered delusions which made her violent. She however took an interest in general topics, corresponded with relatives and friends, and was a shrewd, clever women with excellent memory. Her will made in the presence of three doctors certifying she was mentally competent, was held to be valid.In Chambers and Yatman v Queens Proctor (1840), a barrister was alleged to have strange and eccentric habits. He suffered from various delusions including that he was an object of scorn and contempt to his friends and the whole world. He made a will and committed suicide. The will was held to be valid.Parke B in Barry v Butlin (1838) : the onus probandi lies in every case upon the party propounding a will; and he must satisfy the conscience of the Court that the instrument so propounded is the will of a free and capable testator.In Symes v Green (1859), testator made a will which his nephew challenged. The testator was presumed to be mentally competent since the will was rational and properly executed. Evidence was however produced to show that when he made the will, he was suffering from insanity. The evidence rebutted the presumption of mental competence and the burden of proof shifts to the propounder to proof on a balance of probabilities. Here, the propounder was unable to proof so on a balance of probabilities.In Austen v Graham (1854), testator left a small gift to his brother and the rest to the Turkish Ambassador to benefit the poor in Constatinople and to erect a cenotaph in the city with a description of the testator. The Courts thought that these provisions might be considered absurd and irrational in a native of England and a Christian according to English habits. It was however rebutted by the fact that the testator had in his early life adopted the manners and mode of living of a Mohamedan.In Cartwright v Cartwright (1793), testators will was rational on its face. Thus presumption was that she was mentally competent. However, the presumption was reversed because evidence showed that she was insane six months prior to the execution. The will was however upheld because of evidence that the testatrix had full and complete capacity to understand the state of her affairs and her relations, and to give what was proper in the way she has done.

In Re Bohrmann (1938), testator was diagnosed as a paranoid psycopath. But he had exceptional acumen in managing his rpivate affairs. He left substantial gifts to charities. In his last codicil, he inserted a clause revoking gifts to English charities in favour of American charities. At the time, he was suffering from a delusion that he was being persecuted by the London County Council and he may be dispossessed of his home because of a grudge held against him by one of the Councils valuers. Langton J upheld the codicil with the omission of the offending clause. Prior to this, testamentary instrument has never been divided before under these circumstances. Langton J : It has been the practice in this court for many years to delete from instruments of testamentary disposition anything which the court is satisfied is not brought to the knowledge and approval of the testator. I conceive that I am doing no more now in declaring for this codicil without clause 2 than I should be doing in deleting from the codicil something which I believe was never brought to his knowledge and approval as a sane, balanced man.Templeman J in Kenward v Adams (1975). In cases where the testator is old and infirm, the making of his will should be witnessed and approved by a medical practitioner, who should satisfy himself as to the capacity of the testator and make a record of his findings.In the Estate of Heinke (1959), testator revoked a substantial gift to his housekeeper (who was also his mistress) of 16 years, during a bout of heavy drinking. Judge held that the codicil was void on the ground that the deceased had not been of sound mind, memory and understanding when he executed the codicil and did not know and approve the contents.However, in Chana v Chana (2001), a will was upheld despite the fact that the testator was a heavy drinker but was apparently not drunk. For drunkenness to vitiate the execution of a will, it must have such an effect on the testator that he did not know the nature and quality of the act which he is carrying out