Palairet reported the information to London, who alerted the US Department of the Treasury and the Bank of England.[17] Although the Bank considered the existing security measures were sufficient, in 1940 it released a blue emergency £1 note which had a metal security thread running through the paper. It also banned the import of pound notes for the duration of the war in 1943, stopped producing new £5 notes and warned the public about the danger of counterfeit currency.[18][19]