London to Scotland in under three hours? Well you could go Ryanair and enjoy the bum-rush for seats at Stansted, the teeth-gritting discomfort, and the faint but palpable sense of guilt at your carbon footprint. Or you could jump in Jeremy Clarkson's motor and see if he can repeat his 186mph Limehouse Link dash up the M6. However, the future may herald another way. According to "secret" talks between the UK and Scottish governments,......