The existential threat of nuclear war is no longer a Cold War memory. With nine countries armed with around 15,000 atomic bombs up to 53 times stronger than those dropped in the Second World War, the stakes are arguably higher.

Ahead of the International Day against Nuclear Tests on August 29, we met up British atomic veterans who were present at test sites in Australia and the Pacific, to find out what it’s like to experience a nuclear bomb explosion up close.

While most people know about the bombs dropped on Hiroshima and Nagasaki, fewer are aware that an additional 2,000 atomic bombs were detonated after World War II and tested on hundreds of thousands of young soldiers to prepare them for nuclear war.