Where the Misbourne, centre background, joins the River Colne. The confluence is inaccessible but within sight and sound of the start of the M40 motorway at O.S. TQ 053859. This point is c34 metres above mean sea level, about 100 metres lower than the start of the river at Mobwell Pond. The Colne goes on to flow to the west of Heathrow Airport and joins the Thames near Staines.
Author: Quiller Barrett