Kammala jumla mai zuwa: A lokacin da aka fara Yaƙin Duniya na II, gwamnatin Burtaniya ta nada Purvis a matsayin babban darakta na Hukumar Siyarwa ta Burtaniya, wanda aka ɗorawa alhakin siyan kayan yaƙi daga Amurka. Ya kuma kasance shugaban kwamitin sayen Anglo-French, inda ya yi aiki tare da Jean Monnet. A watan Yunin 1940, lokacin da Faransa ke gab da kammala yarjejeniya
yarjejeniyar tsagaita wuta da Jamus, Purvis ya shirya ya karɓi duk kwangilar makamai na Faransa da ke jiran a Amurka a farashin dala miliyan 612. Purvis ya yi shawarwari ga Birtaniya a watan Satumbar 1940 don tabbatar da abubuwa kamar jiragen ruwa na torpedo, jiragen sama, da kuma makamai da Amurka za ta ba Birtaniya baya ga masu hallaka 50 a matsayin wani ɓangare na Yarjejeniyar Destroyers for Bases.