On a Moscow bridge in 1960, a decorated Soviet military intelligence officer pressed a package into the hands of American students and begged them to take it to the US Embassy. This episode explores Oleg Penkovsky, the highest-ranking Soviet official to spy for the West at the time, and how his intelligence reshaped the Cuban Missile Crisis.

Driven by a career derailed when the state uncovered that his father died fighting the Bolsheviks, Penkovsky turned personal grievance into an ideological crusade. Using a Minox camera and couriers, he handed over documents that exposed the Soviet missile bluff and gave Kennedy a decisive advantage before his arrest and execution.

• His father's death in the anti-Bolshevik White Army was a hidden mark that eventually ended his career
• British intelligence used businessman Greville Wynn a ...