There is some evidence '' Luton/Hemel Hempstead Evening Post Echo '' newspaper that strongly suggests this facility was used as a CIA weapons dump . This weapons dump held Soviet Bloc small arms ( AK 47s , RPGs , etc. ) for a special combined CIA/MI6 Cold War operation , code named Operation GLADIO . The specific duties of Op . GLADIO operatives was " behind the lines " resistance activities . The concept was that IF Western Europe was invaded by the Warsaw Pact , that such units could disrupt the invaders " lines of communications and supplies " . Duncan Campbell , in his title War Plan UK & The Unsinkable Aircraft Carrier , refers to this base facility by its CIA radio call-sign of " X-Ray Zero Niner " . Today , a number of the strengthened ( although NOT armoured ) ammo block houses still stand on the industrial estate . The scrap yard near the far end of the estate retains the two earth concrete revetment walls , that allowed truck access to the block house doors . It also gives some scale of the removed earth bund revetment beams carefully constructed around ALL the block houses ( prior to their demolition for industrial units ) . The presence of the base was exposed shortly after the events from The Great Train Robbery took place nearby , when a BBC current affairs programme , a few weeks after the Great Train Robbery , exposed the base to the world
The Great Train Robbery
Great Train Robbery (1963)
RAF Cheddington