A fine seems pretty low for this sort of offence, but the clue might be in the mitigation that was put forward “The man, from Cresselly in Pembrokeshire, separated from his first wife in 2010 and launched divorce proceedings the following year. He claimed that he had filed for divorce online and assumed it had gone through.”
Apparently, it was the vicar’s fault – “the man had “presented the paperwork to the vicar who married them” without any issues raised” instead of pointing out the problem.
The magistrates took account of that and fined the unnamed gentleman £400 and ordered him to pay £400 in costs (and presumably a Victim Surcharge).
But it does raise the question of whether it’s fair to convict someone of bigamy when they didn’t know that they were committing the offence.
Bigamy – the offence
This is contained in s57 Offences Against the Person Act 1861 :
Whosoever, being married, shall marry any other person during the life of the former husband or wife, whether the second marriage shall have taken place in England or Ireland or elsewhere, shall be guilty of felony, and being convicted thereof shall be liable . . . to be kept in penal servitude for any term not exceeding seven years
Provided, that nothing in this section contained shall extend to any second marriage contracted elsewhere than in England and Ireland by any other than a subject of Her Majesty, or to any person marrying a second time whose husband or wife shall have been continually absent from such person for the space of seven years then last past, and shall not have been known by such person to be living within that time, or shall extend to any person who, at the time of such second marriage, shall have been divorced from the bond of the first marriage, or to any person whose former marriage shall have been declared void by the sentence of any court of competent jurisdiction.
On the face of it this is what is called a ‘strict liability‘ one – the fact that someone doesn’t know that they are committing bigamy is no defence.
Courts generally dislike strict liability offences, as it can lead to results such as this. It was confirmed in Gould  2 QB 65 that if someone genuinely and reasonably believes that they are free to marry, then that is a defence.
It leaves aside the question of whether an unreasonable belief would be a defence, but under general principles it would be.
Although that may sound odd, obviously the less reasonable belief, the the less likely a jury is to accept it, but the general rule of the criminal law is that people are judged on the facts as they believe.
The exception to that is sex cases where, since the 2003 Act, there is a requirement of reasonableness. But, if a Court were asked to rule on the issue, I would imagine that they would rule in line with the general rule.
Where does that leave Mr X?
We’re not saying that he isn’t guilty, we don’t know the facts etc. It may well be that he did not believe that the previous marriage had legally ended, or he concluded that there was not reasonable grounds and that that was the correct test, or for some other reason he decided to plead guilty.
But for somebody in his position, there is a defence – this is a good example of the general pragmatism of the criminal law, as well as the fact that we tend not to criminalise people unless they have done something that they know or believe to be wrong.