Kammala wannan jumla: Bayan barkewar Yaƙin Duniya na II, gwamnatin Faransa ta aika Rapkine zuwa London a watan Janairu 1940, a kan wani aikin hukuma don tabbatar da samar da kwal don masana'antar Faransa da dalilai na soja. Duk da yake a Ingila, ya taimaka wa James Crowther wajen ƙirƙirar Anglo-French Society of Sciences don tabbatar da hadin gwiwar kimiyya tsakanin ƙasashen biyu. A watan Yunin 1940, bayan
Lokacin da Faransa ta mika wuya ga Jamus, Rapkine ya yi kira ga Society don taimakawa masana kimiyyar Faransa su sami mafaka a Burtaniya, amma Society ya rushe lokacin da tashin hankali tsakanin Faransa da Ingila suka hana haɗin gwiwar kimiyya. Rapkine da Henri Laugier sun bar London don ci gaba da kokarinsu a Amurka.