NB v MI  EWHC 224 (Fam) engages capacity to marriage. A marriage was formed on 1 June 2013 in Pakistan under sharia law between the parties. 18 years earlier, when she was 6, the wife was involved in a serious accident which left her among others badly neurologically damaged. She only slowly recovered from these injuries, to the extent that expert evidence suggested she does now, but did not have capacity in all the areas of life canvassed including to marry and enter sexual relations, at the time of her 2013 marriage.
Mostyn J considers the issues of whether partners understand the constituent elements of what it means to get married, starting with Durham v Durham  10 PD 80 and of course noting the changed approaches to the institute of marriage since. The core test then is to check whether at the time of marriage, the partners understood what it means to get married: financially, emotionally, sexually.
Mostyn J upon review of the evidence held that the wife lacked awareness of the difference between Islamic and English marriage; or the financial consequences depending on the contract; or her husband’s potential claims against her estate; or her husband’s proposed living arrangements. Yet that these say nothing at all about her capacity to marry : ‘They may say quite a lot about her wisdom in getting married, but that is not the issue I have to decide.’ Although reference is made to KC & Anor v City of Westminster Social & Community Services Dept. & Anor  EWCA Civ 198 I find the conflict of laws analysis could have been made clearer: is the overpowering engagement of English law a finding of confirmation of lex domicilii (the lex patriae of the wife is not mentioned but might be British), entirely disregarding a role for the lex loci celebrationis?
This is not my core area – I imagine others may have a more expert insight.