Inside the shadowy world of anti-Putin sabotage from within Russia

Two Russian men secretly working for Ukraine's intelligence services have given rare accounts of operations they claim to have been involved with, that have targeted military assets and personnel inside Russia. One of the men, whom we are calling Ivan, claims to have played a role from Russia in Ukrainian drone attacks on strategic bombers and munitions factories on his home soil. He features in a BBC World Service documentary about the shadowy world of Russian saboteurs. The documentary, by independent Polish journalist Marcin Mamon, also features a man we are calling Foma, a Russian living in exile in Poland.