I expect there to be huge amounts of commentary about this, but Araba Taylor certainly seems to have done a good job here: she has provided enough argument for the judge to be convinced that the MCA does not apply to tests of capacity of deceased persons and the validity of the wills made.
This is quite a massive step – since the Act introduced a new set of distinct tests for capacity, there has been a question over whether the MCA test for testamentary capacity was the same as, or superceded the common law test. Most textbooks have been decidedly woolly on the subject – saying it was a rephrasing of the common law in modern language – Banks and Goodfellow is quite old now… (over 140 years) and one might think that our understanding of mental awareness has increased over the intervening years.
This judgment suggests that the MCA test is higher than the common law test – which sets the bar lower – partly because many people who make their wills do so when elderly and infirm, and sometimes when they need the help of others to fully comprehend their circumstances so they can make effective decisions. And that this cannot have been intended by the lawmakers at the time.
23. A second difference arises from section 3(1), which requires a person to be able to understand all the information relevant to the making of a decision. This, at least arguably, may in some cases require more of the testator than the common law test, which concentrates on whether the will correctly represents the testator’s intentions and his appreciation of the claims to which he ought to give effect, but does not require in all cases that he is able to remember and understand all relevant information. See Banks, above, Fuller v. Strum  EWCA Civ 1879 at  and paras. 32-3. below.
24. A third difference is that the effect of section 3(1) read together with section 3(4), if applicable, would render a will invalid if the testator was unable to understand, use or weigh information as to the reasonably foreseeable consequences of the choices open to him, because of the impairment of his mind or brain. Presumably, that would be limited to material consequences, that is consequences which the testator might reasonably be expected to take into account, but this too probably requires more of a testator than the Banks test, at least in some cases.
It seems that the judge here has considered that the common law test should be determinative when considering whether wills are made validly, and that the MCA directions more correctly apply to the statutory wills regime (whereby the Court of Protection sanctions a will that the patient would have made, had they had capacity). This is also relevant when challenging wills, because of the burden of proof that lies with the propounder of the will to prove that any doubts as to validity have been allayed, once a suspicion has been roused. The MCA presumes capacity, wherever possible.
In addition, the rest of the MCA is all about assisting patients with decision making and autonomy when they are living, rather than examining the decisions that have been made.
The judge in this case wondered whether it was possible for any testator to fully give all considerations to the material consequences of their decisions. Perhaps some of the decisions made in a will might be dependent on legal advice as to their efficacy. In the circumstances of this case, the testatrix left a life interest in what she had (which included an unresolved interest in the former matrimonial property) to her partner (remainder children), and then from the residue, she left part to her children and part to her partner. The partner was of the same generation as the children. The practical effect of a life interest would mean that her children would be unlikely to benefit in their own lifetimes, but it would be for the grandchildren to benefit in due course. Was the letter (which may or may not have been written by the testatrix, and probably by her partner, but signed by the testatrix) written to explain the rationale behind the decisions she made enough to show that she had a full understanding of the effect of her will?
In this decision, having weighed considerable evidence, the judge thought that the testatrix’s side letter did show some reflection on the consequences of having a life interest.
As a side note, the judge did consider that it might well have been prudent to seek medical advice at the time of taking instructions, as per Kenward and the Golden but tactless rule…