I saw a graduate magazine in my university careers office a few months ago and off the top of my head i believe that the national average starting salary for graduate engineers is approximately 20-21K. Obviously that will be subject to regional variations etc. YThe magazine said you can add an extra 1K per year onto that figure if you have a PhD apparently. Although as portsharbourflyer has already stated if you are being recruited onto a graduate scheme or into a standard graduate position don't expect to get anymore than anyone else for your PhD. At the end of the day its a recruiters market and if you don't want to take the low-paid job to get your foot in the door somebody else coming behind you probably will. The only sad thing about that is that alot of good people are doing aerospace degrees etc. and then going off into other higher paid sectors such as finance.
I agree with Genghis work experience is vital! If you are doing a PhD which involves extensive wind tunnel testing or CFD code development/ CFD commercial package use then you can expect that to stand you in good stead for going into industry too, so long as you don't mind going into the industrial research sector.