From the Ministry of Justice website, the magistrates have an oath: 'If you are appointed, you will be required to swear that you "will be faithful and bear true allegiance to Her Majesty Queen Elizabeth the Second, her heirs and successors, according to law" and that you "will well and truly serve our Sovereign Lady Queen Elizabeth the Second in the office of Justice of the Peace, and will do right to all manner of people after the laws and usages of this realm without fear or favour, affection or ill will".' The problem that Andrew McClintock has is that he doesn't think that same-sex couples count under the all in all manner of people. Bystander in his Magistrate's Blog points out that he believes that as a JP Mr McClintock's boss is Her Majesty, I unfortunately can't find an official report online to confirm whether the action was taken against the crown, although it technically may have been anyway even if the tribunal considered the government department to be the employer.
I did at the time of reading about this wonder what the Church of England position was on the whole thing, given that the established church and the judiciary all report to the same MD, in a manner of speaking. I found out listening to PM last night; of the two people brought on from each side of the debate, the Bishop for Urban Life and Faith, Rt Rev Stephen Lowe was on the side arguing that what was best for the children was paramount and that was a loving family, no matter how that family was composed. I was impressed, now if only they had that compassion towards gay clergy.