Additionally , the land belonged to the army and a base with men and workshops was at hand .
The British experienced a stroke of luck in November 1939 when a German mine was dropped from an aircraft onto the mud flats off Shoeburyness during low tide .
The land belonged to the army and a base with men and workshops was at hand .
The British experienced a stroke of luck in November 1939 when a German mine was dropped from an aircraft onto the mud flats off Shoeburyness during low tide .