On this day 1940, the 5,136 ton Denholm Line cargo ship SS Broompark sailed from Bordeaux as part of Operation Aerial, the final evacuation of British & other forces from France after #Dunkirk. Aboard were Profs Lew Kowarski, Hans Halban & 33 of France’s finest nuclear scientists

Kowarski, Halban & team brought with them machine tools, industrial diamonds, their supply of deuterium oxide (heavy water), & crucially, their knowledge, all of which was incorporated into the curiously codenamed “Tube Alloys” project, Britain’s burgeoning nuclear bomb programme

Meanwhile in London, newly evacuated Polish Prime Minister, Minister of Military Affairs & CinC, General Wladyslaw Sikorski was meeting British Prime Minister Winston Churchill, promising that Polish forces would fight alongside British until final victory.

Echoing Brig/Gen Charles de Gaulle's speech to the people of France the day before, Sikorski also made a speech, broadcast by the BBC, calling all Polish forces still fighting in France to evacuate to Britain & join him (& the Navy, which had arrived in 1939) to continue the war.

Embeded in French armies, this proved difficult for many Polish troops, some unable, others unwilling to leave their allies. Meanwhile, much of Operation Aerial had concluded on the 18th, leaving key ports in ruins, shipping sailed & RAF air cover flown https://twitter.com/navalhistorian/status/1273710756207505425?s=20

Nonetheless, @RoyalNavy CinC Plymouth & Western Approaches, Adm Sir Martin Dunbar-Nasmith, pledged to make shipping available & continue the evacuation.