The first truly safe (for the person throwing it) British hand grenade was the Mills bomb, invented by English William Mills in 1915. This was a fragmentation grenade, so the damage was intended to be caused by the shrapnel from the shell of the grenade exploding outwards. These were deadlier to the enemy yet safer for the user; so much so that these changes revolutionized trench-war combat.

Britain manufactured millions of Mills bombs pins during the course of World War I, and it remains one of the most iconic weapons of the 20th century.