Rubuta ci gaba don wannan sakin layi - A lokacin da aka fara yakin duniya na biyu, gwamnatin Burtaniya ta nada Purvis a matsayin babban darektan Hukumar Siyarwa ta Burtaniya, wacce aka ba da alhakin sayen kayan yaƙi daga Amurka. Ya kuma kasance shugaban kwamitin sayen Anglo-French, inda ya yi aiki tare da Jean Monnet. A watan Yuni na shekara ta 1940, sa'ad da Faransa take gab da ƙulla yarjejeniyar tsagaita makamai
tare da Jamus, Purvis ya shirya ya karbi duk kwangilar makamai na Faransa 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.