 With the completion of the route, the Chowns Mill roundabout to Thrapston roundabout section of the A605 was renumbered the A45 and the A45 to the east of Higham Ferrers was renumbered A4500.Thrapston is now the terminus of the A45 and the start of the A605.Just before the A14 was built, a short section of the A605 was built bypassing Thrapston to the east to the A604 (as it was then known).