Tensions between the US and North Korea are running high. Kim Jong-Un has been testing long-range missiles and nuclear weapons. The Trump administration wants Pyongyang to end its nuclear weapons programmes and has said “all of our options are on the table” in pursuit of that goal. North Korea has said that a "super mighty pre-emptive strike” is planned if the US uses military force against them. But – our question this week – how did this poor and isolated country develop nuclear weapons in the first place?

Presenter: Ruth Alexander

Producers: Kate Lamble, Phoebe Keane and Estelle Doyle

(Photo: North Korean leader Kim Jong Un meets scientists and technicians in the field of researches into nuclear weapons. Credit: Reuters)