What is the difference between a 15-year-old school-leaver with no support, and a 17-year-old school-leaver with no support?
There's a heck of a lot in terms of maturity, confidence, ability, understanding of how life works, street knowledge, responsibility. (Not that either age group should be unsupported).

I think it's a great idea, provided that there are plenty of options that fit the variety of needs. VCAL has been a great move for the youngsters who aren't geared towards reading textbooks and sitting in a traditional classroom. Kids who come out of VCAL in my experience are quite a lot more worldy and well equipped for the workplace and to stand on their own two feet, than a 15 year old who leaves school in year 10.