There is no particular "route". Working for BA, have you looked into the Future Pilot Programme programme they offer? I think you require a B in Maths - check it out though, you may need A-Levels and/or a degree!
I too have a dream to become a commercial pilot! I'm current at Uni studying Aircraft Engineering whilst training for my PPL. I hope to add my night rating and IMC rating to it once I pass it. From there, I don't know. I had a "route" when I was 13, if that panned out I should have my ATPL by now! But plans change. I'm just going to keep plugging away, keep checking this forum, speak to the airline pilots I know already and keep working hard to achieve becoming an airline pilot.
PS. take a look at CTC Wings cadet. They offer to take you from no or little flying experience to Frozen ATPL, they also have good working links with Flybe and BA.
Hope this helps dude.
Good luck!
