I don't remember politics ever being discussed at junior school.
My political discussions at home as a teenager were always with my dad who had Liberal leanings -mum was a great admirer of Thatcher -mainly because she was a woman and the first of her kind.
I was completely the opposite and remember having some ding-dong rows while watching Question Time mainly but they always listened to what I had to say...they didn't agree as I saw things in a very clear cut way back then -no half-measures, but they always allowed me my say...
I said some terrible things to dad who was a design engineer and just before the time of the Falklands war had actually worked on anti-personel devices - his defence was that if he didn't do it someone else would have...he also worked for a long time in nuclear power...which I loathed... They never told me to shut up and I probably (definitely)exagerated
It has never been mentioned since and we never talk about politics now...
I don't think that a teacher should talk about their own views at a junior school level in any case.