<Dd> 16: The first British civilian casualty occurs when a German bomber kills James Isbister in an air raid on Orkney in Scotland . </Dd> <Dd> 17: The IRA is blamed for bombs set off in London . </Dd> <Dd> 20: The Luftwaffe and German U-boats start mining the Thames estuary . </Dd> <Dd> 23: Polish Jews are ordered to wear Star of David armbands . </Dd>

What year did the soviet union announced its neutrality