Well, it all depends on the number of qualifications and age and experience (and of course the job and where you work). With a good grade BSc you would expect to start earning around £18-20K a year and then that would increase as your experience increased so in a short time you should expect to earn up to £30K a year. People with doctorates should start on between £25-30K a year and should expect to be earning anything up to £50K a year given time and assuming they are good at their job. There are wide exceptions to these figures though and I am lucky to be paid a lot more than that – although I do work about 80 hours a week on average.
Just as important as getting a good salary is the fact that, as a scientist you are more likely to have an interesting and varied job that you enjoy doing, rather than some boring repetitive job that you only do for the money. That’s worth a lot.