Melanie Shee's reply:
There is no fixed route to becoming an illustrator. You do not need to go to university to work as an illustrator and there are other pathways such as apprenticeships, however, as you are already on an apprenticeship which you are considering leaving may not bode well for you securing a further apprenticeship. As you may be aware securing an apprenticeship can very competitive so you need to bear that in mind if you do decide to go down this route.
Although as I said you don’t need to be a graduate to work in this sector you need to remember that will be competing with graduates who have very specific design portfolios. Do you have a strong portfolio (now often digital) that you can show prospective employers? If not will need to develop a professional portfolio that is on par with graduate level work. You can look at a wide range of portfolios on the Association of Illustrators site http://www.theaoi.com/portfolios web site so you can the level of work expected.
A formal education, be it at a university or college means will also mean that you will have developed the skills and knowledge of the sector and be competent in using the specific software used in every design office such as Photoshop, InDesign and Illustrator which you may not have used before. You can teach yourself these programmes but you will be expected to very competent it using them.
May I suggest you look at job descriptions out that at the moment and look or try gain experience via a short placement in a graphic studio, or at the very least contact an illustration company for advice on what they look for when employer illustrators, as this will help your understanding of the skills required when they are recruiting. However, you also need to be aware that may illustrators are freelance and work on a commission basis only. You need to think is freelance working for you?
One area you could consider is becoming a Technical Illustrator. Technical illustrators, prepare detailed drawings to help people understand often complex scientific or technical information. Their illustrations are used in textbooks, reference books, instruction manuals and technical sales brochures. This may be one way in which you could combine the knowledge and skills you will develop on your current engineering apprenticeship then move into illustration once you have successfully completed your apprenticeship. May I suggest you contact The Institute of Scientific and Technical Communicators http://www.istc.org.uk for advice if this is an area that appeals to you/
Good luck whatever path you decide to take. Melanie