The catchment area could be a lot bigger than people believe. I live near Carlisle and the number of taxi firms that advertise fares to GLA/PIK/NCL/EDI/MAN/MME starting at 150 return take up a few pages in the phone book.
Unfortunately I drive trains for a living and the first class return fare from Carlisle to Euston is well over 350.
Surely some carrier could do a Mon/Fri out and back with a 70 seater and undercut the Virgin hegemony.