This web page is from www.thehs2.com, a project to document the HS2. The underlying map on this web page is provided by OpenStreetMap and its contributors. It is released with the Creative Commons Attribution-ShareAlike 2.0 licence.

A Department for Transport web page provides the post consultation route as an ESRI shape file. This file is released with an Open Government Licence. I've converted this file to GeoJSON. This GeoJSON is used to generate the multi-coloured line.