If you decide on the military route then beware! The current situation does not bode well for the airline industry for the coming months/years. As the industry is basically cyclical then this comes as no real surprise.
The military is a well trodden path to the airlines. However it takes time, commitment and dedication. The CAA dispensations to military pilots as far as hours flown and exams required don't start until at least 2000 hours. New JAA accreditation are floating about somewhere and it is unknown if any dispensations will be given at all! Given that many squadrons 'average' monthly flying rate will be 15-18 hours per month and taking leave and ground duties into account you won't be hitting the magic number for a fair few years. Most recruiting stations would boot you out of the door if your 'primary aim' was a short cut to civil flying cheaply. As would most training squadrons. Add in that the return of service for the military will be at least 6 years and you will be starting your 'civvie' career late. The up sides are camaraderie, fantastic flying and lots of fun. Plus the ability to fly aircraft and helos to the limits of their operational ability.
Otherwise go for a recognised flight training school, work hard, pass everything first time and hope you get picked up by a good carrier. Downside, expect to pay upto £85,000-£120,000 for your training. Upside, early into a carrier if you're lucky and a good start on the 'seniority' ladder.
Good luck.