Denham, UK. 6th April, 2021. HS2 security guards and enforcement agents fence off an area during tree felling in Denham Country Park for electricity pylon relocation works connected to the HS2 high-speed rail link. Thousands of trees have already been felled in the Colne Valley where HS2 works will include the construction of a Colne Valley Viaduct across lakes and waterways and electricity pylon relocation.