May I introduce my wives?

The question of polygamy and the English law has come to the fore again following a ruling that a man with more than one "wife" can claim any benefits to which he may be entitled in respect of each of them. The usual immediate response to such a story is "... but isn't bigamy a crime?" Well, yes but just what constitutes bigamy? It's marrying somebody whilst still being married to somebody else. The essential word there is "marrying". My understanding is that the law of bigamy only applies to marriages which have taken place, or are deemed to have taken place according to English law. Whilst the law recognises marriages contracted under other law or custom provided they were legal under that law or custom when and where entered into, they are not marriages under English law and therefore not subject to the law of bigamy. This is why I put the word wife in inverted commas. And of course, now that living with a partner (and maybe more than one) outside marriage no longer raises any eyebrows, it can be argued that the concept of bigamy is somewhat outdated.