So i have applied for and been accepted on an MPhys Mathematics and Physics degree. I'm really happy but am also a little unsure as to whether i have made the right choice. My goal is to go straight from my MPhys to a PhD in Theoretical Physics. I have looked on the internet and advice seems to differ as to what is the best combination I have the option to change my choice early on in my first semester so i ask you this. What is my best option for a PhD in Theoretical Physics? A joint Mathematics and Physics degree? Or single Mathematics or Physics? Cheers.