During the Second World War, Pertwee spent six years in the Royal Navy. He was a crew member of and was transferred off the ship for officer training shortly before she was sunk by the German battleship "Bismarck", losing all but three men in May 1941. Later, he was attached to the highly-secretive Naval Intelligence Division, working alongside future James Bond author Ian Fleming, and reporting directly to Prime Minister Winston Churchill and Deputy Prime Minister Clement Attlee. In an interview conducted in 1994 and published in 2013, he said, "I did all sorts. Teaching commandos how to use escapology equipment, compasses in brass buttons, secret maps in white cotton handkerchiefs, pipes you could smoke that also fired a .22 bullet. All sorts of incredible things." During his time in the Navy, Pertwee woke up one morning after a drunken night out while in port to find a tattoo of a cobra on his right arm.