Since graduating I've been working in a lab to get some experience, and have decided that I really enjoy research (in microbiology/molecular biology). I'm now considering doing a PhD, but I would like to eventually move into industry and hopefully work for R&D with a large company. Does anyone know whether doing a PhD would help or hinder this move?

If you want to work in R&D then a research degree i.e. Mphil or PhD can only help.

An academic qualification can never replace real experience in the field. If you are already working in the field than dont go for a phd.

A PhD would help a career in research.

a PhD will definately help a career in industry if you have high aspirations. It is imposible to get high in the company without one!! If you just want to continue working in the lab for the rest of your career then don't worry about a PhD