From Heathrow Terminals 1-3 train to Paddington Underground Station, Tube to Oxford Circus Underground Station, Tube to London Euston, then train to Northampton. 1hrs 48min £52. From Heathrow Central Bus Station line 724 bus to Watford Junction then train to Northampton. 2hrs 16min £23. From Heathrow Central Bus Station line 230 bus to Brook Furlong, Milton Keynes Coachway then bus to Delapre Crescent. 2hrs 14min £17. From London Heathrow Airport (LHR) drive to Northampton. 1hrs 10min £14.