For instance, even if a person is deemed to lack capacity to amend an earlier will which itself has not been made in contemplation of marriage, if they retain capacity to marry then that marriage would still revoke that earlier will.
Further still, a will remains revoked by marriage even if the testator (the person who made the will) is subsequently deemed to have lacked capacity to marry.
Even more extraordinary is that, even if a marriage is subsequently annulled because one of the parties did not have the capacity to marry, it will still revoke their previous will. This was affirmed in the case of Re Roberts  1 W.L.R. 653.
Capacity to marry vs. capacity to make a will
Under section 3 Mental Capacity Act 2005, a person is deemed to have capacity to marry if they are able to understand, retain, use and weigh up relevant information as to the reasonably foreseeable consequences of marriage, and communicate their decision.
Even before the legislation came into force, case law confirmed that the test for capacity to marry is a low one, and is lower than the test for testamentary capacity.
In Sheffield City Council v E and another, Sheffield City Council brought an action to prevent E (a 21 year old girl who suffered from spina bifida and who, the council suggested, functioned at the level of a 13 year old) from marrying S (a 37 year old man who had previously been convicted of sexually violent crimes). The council was concerned for E’s welfare; namely that she was at risk of domestic violence and sexual exploitation by S.
The council were, understandably, reluctant to suggest that E did not have the capacity to marry anyone at all, and the High Court subsequently held that the relevant test was whether a person had the capacity to understand the “nature of the marriage contract” and the “duties and responsibilities that normally attach to marriage” and not whether the person understood the implications of marriage to a particular person, or whether it was wise to marry at all. Munby J confirmed that the contract of marriage was a simple one and did not require a high degree of intelligence to comprehend.
The court warned that it had no jurisdiction to determine whether marriage in general or an individual’s particular marriage was in their best interest, and advised that the test of capacity to marry must not be set too high, “lest it operate as an unfair, unnecessary and indeed discriminatory bar”.
The more recent case of EJ v SD has, however, provided some valuable protection for vulnerable testators. In that case the court held that a person should be able to “understand, retain, use and weigh information as to the reasonably foreseeable financial consequences of a marriage, including that the marriage would automatically revoke the person’s will”.
You can read our blog on the recent decision of EJ v SD here.