Construction was completed in June 2013. Original plans were to build the embankment using aggregate trucked in from elsewhere, but eventually it was decided to build up the embankment using chalk taken from the nearby Wilbury Hills, low-lying chalk hills forming part of the Chiltern Hills, from less than away, removing the need for lorry movements along public roads. The chalk was quarried from just beyond the ancient Icknield Way, which at this point is a public bridlepath between Ickleford and Letchworth Garden City, and the contractor was required to refill and replant the quarry afterwards.