After completing a PhD in Particle Physics I left academia and have been working in industry for a few years now. However, during that time I've become more and more interested in Pure Math, to the point that I am considering trying to go back to academia and pursue my interest in full.
However, since the topic is so different from my PhD, I realise this would involve doing another PhD, if not a MSci before that. The grades that got me into my first PhD (an MSci equivalent degree) were not bad, but perhaps not enough to get me into a top MSci/PhD program now. My PhD dissertation, on the other hand, was awarded the maximum grade.
My question is: is it possible to use a previous PhD as an entrance degree to a second MSci/PhD? Would this be regarded positively by a top-level admissions committee?
As background, my first MSci and PhD were in Spain, and I am considering studying either in the UK (my current residence) or Germany.