“When the 1939-40 Football League season kicked off on Saturday 26 August 1939, players were wearing numbered shirts for the first time. Bigger changes were to come. Germany invaded Poland the following Friday and the four divisions and FA Cup were halted once war was declared on 3 September. The action stopped after three rounds of fixtures, with Blackpool boasting the only 100% record in the top flight and Leeds bottom of the table having failed to score a goal. …”
Guardian