 Grimsbury is on a floodplain and suffered severe floods in 1998 and 2007.Workmen found a fizzing and burning incendiary chemical that was suspected to be left over from a long-demolished First World War munitions factory and ammunition testing range.Thames Valley Police closed the Tesco Express, The Pepper Pot pub and the Atlantis Fish bar and set up a cordon on 19 April 2012.