The truck in on the M25 motorway,which crosses the valley at this point. see http://www.english-heritage.org.uk/server/show/nav.12114/chosenImageId/2 see http://www.eppingforestdc.gov.uk/Council_Services/planning/conservation/HILLHALLTHEYDONMOUN T.asp see http://en.wikipedia.org/wiki/Stapleford_Aerodrome see http://www.british-history.ac.uk/report.aspx?compid=15709