[EdLUG] How do I become a security researcher/pen tester?

[Rocketmail]

Sorry if this is the wrong place to ask this, but:

I'm going into my final year of a computational physics degree, and I 
think I might like to work in a computer security area after university. 
I have some programming knowledge, an interest in the field and of 
course I use linux. I can also take the computer security and secure 
programming modules from the computer science department (I can even 
take a quantum security module :D ).

What sort of qualifications/level of knowledge would I be expected to 
have to start working for a pen testing company, or in security research?

Thanks,
- Calum