The Tribunal have just issued a determination holding that proxy marriages in Brazil must be recognised in English law. The case is called CB (Validity of marriage: proxy marriage) Brazil  UKAIT 00080.
There seem to be a lot of these Brazilian proxy marriages about at the moment. I had an email query about them a few weeks ago and suddenly several cases landed on my desk a week ago or so.
A marriage by proxy is where one of the parties to the marriage is represented at the ceremony, rather than being present in person. It is a rather odd concept but it is legal in Brazil, and quite a few other countries for that matter.
There is a rule in international private law that a marriage that was valid in the country in which it took place will be recognised as valid everywhere else in the world. There is a famous dictum by Viscount Dunedin in Berthiaume v. Dastous  AC 79 to this effect that I won’t quote here and it is also covered at Rule 67 of Dicey 14th edition. In fact there do seem to be exceptions to it, as the French, for example, have a provision in their law that prohibits recognition of marriages in certain circumstances. We have no equivalent laws here, though.
It also means that a party to a polygamous marriage can enter the UK as a spouse. However, immigration rule 278 prevents a second wife (it always a question of multiple wives, not husbands, in my experience) entering the UK as long as the first wife is still the wife of the sponsor. If the first wife dies or is divorced, though, another wife is allowed to enter.
The one case that I’ve come across that does not make much sense in this regard is a very sad one called KC & Anor v City of Westminster Social & Community Services Dept. & Anor  EWCA Civ 198. In it, the courts declared as invalid a telephonic marriage (as in one that was conducted by telephone) between a severely mentally disabled adult in the UK and a woman in Bangladesh. The grounds for holding it invalid were capacity, and an unusual new legal rule that a marriage valid in the country in which it took place could nevertheless be struck down in the UK if “sufficiently offensive to the conscience of the English court that it should refuse to recognise it.” Rather than relying on this novel approach, I always wondered why they held that the marriage had taken place in Bangladesh when one of the parties was physically present in the UK. It was also a point flagged up by the Court of Appeal in their judgment.