From Heathrow Terminal 1 train to Paddington (H&C Line)-Underground, Tube to London Euston, then train to Northampton. 1hrs 33min £41. From Heathrow Central Bus Station line 140 bus to Harrow & Wealdstone then train to Northampton. 2hrs 13min £19. From Heathrow Central Bus Station line 230 bus to Brook Furlong, Milton Keynes Coachway then bus to Northampton, Coach Park. 2hrs 42min £14. From London Heathrow drive to Northampton. 1hrs 21min £14.