Time Bomb In Whitehall Colonial Office After Gruner Execution - Dover House, Whitehall (London), where the bomb was found. A time bomb made up of 27, sticks of gelignite was found in a sub-basement women's cloarkroom at Dover House, Colonial Office building in Whitehall, London, by Mrs. Charlotte Elizabeth Hart, a cleaner who lives at Halston House, Kennington (London). The bomb, powerful enough to have blown off the roof, is be lived to have been planted as reprisal for the execution of Dov Gruner, Palestine terrorist. It was wrapped in brown paper and tied with string. When Mrs. Hart revealer her discovery tot he security officer in the building, special security measures were put in force at all Government buildings in Whitehall. April 16, 1947.