Crewmeal,
That's the point though, at present BHX is largely reliant on the West Mids for it's catchment, given this fact it is doing very well, better than any other English airport in the same position by a long stretch. If the plan behind this is to entice passengers from the South East to BHX then clearly we have a much bigger catchment area with which to play with, BHX would cease to be a regional airport it would become a gateway. In realistic terms though who outside of the M40 corridor or North London would consider it? Let's have it right if you live near the Northen Line, BHX is easier to get to than any London airport, swap the tube for the mainline at Euston and you're pretty much there. Getting the airlines to cater for them is a different matter, it's the chicken and egg scenairo....