New UK Labour Party leader Jeremy Corbyn refused to sing the National Anthem at a service commemorating the Battle of Britain. He is against the monarchy, which is his prerogative. Perhaps he doesn't want God to save the Queen.
Question: he is a member of Parliament. Did he take the following oath, required of all MPs before taking their seats? Could he explain why he took a monarchist oath, but refused to sing a monarchist anthem?
He is entitled to be a republican and work toward the abolition of the monarchy. He is not entitled to misrepresent himself. To be an MP, he doesn't have to be a monarchist, but he must be loyal to the constitution as presently constituted, even if he subsequently works to change it.
Additionally, he is a pacifist. That is very sweet, but is it his intention to disband HM Armed Forces?