Applying to a second MSci/PhD with a PhD 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.
If you got the maximum grade on a dissertation in another PhD program, that would be viewed positively. The admissions committee would be hoping that you will do the same in their program.

The basis for concern is that your pre-dissertation work will "average down" the value of your application. It's not something to be ignored, but most admissions committees will give the greatest weight to 1) the highest level of work that you have achieved and/or 2) the most recent level you have achieved. in both cases, your PhD dissertation grade is a big help.

I might refrain from taking math courses until getting into a program, even at the expense of being less prepared. Because if you take those courses and do badly, that becomes the new "most recent."