In his radio speech delivered in London on 5th May 1943, addressed to Poles in German-occupied Poland, General Władysław Sikorski, Prime Minister of the Polish Government in Exile, appealed: ‘The greatest crime in the history of mankind is being committed. I know you’re helping the persecuted Jews to the extent that you can. Thank you, citizens, on my own behalf and on behalf of the Polish Government. I ask you to provide all possible assistance to the Jews in Poland and to try to oppose this terrible cruelty’.