BR used to recruit from drivers on locos on private sidings. But then in BR you progressed through "links" onto pasenger trains then the expresses and getting better pay. The rosters were worked out by management and union reps together.My cousin trains train drivers for Northern Rail. Guess what they do once they're fully trained up? They go to Virgin for the better pay. He says it's happening all the time,NR can't keep a hold of them.
NR simply don't have the drivers required, apparently.