 Nyora kupfuurira kweiyi ndima - Crabtree akapinda Stonyhurst College. Musi wa 5 Gunyana 1914, mazuva mashoma mushure mekutanga kweHondo Yenyika Yekutanga, Crabtree akanyoresa sevanhu muLoyal North Lancashire Regiment. Rinopfuura gore gare gare, akagadzwa kuva mukuru mukuru wechipiri. Crabtree akakuvadzwa pedyo neMorval mukati meHondo yeSommemuna September 1916 uye akaona mamwe mabasa kuArras nePasschendaele mushure mokupora kwake. Akakunda Military Cross nokuda kweushingi hunoshamisa uye kuzvipira kubasa musi wa 26 September 1917. Kwapera mwedzi mumwe chete, akakuvadzwa kechipiri uye haana kuzoshanda kuWestern Front kwehondo yose yakanga yasara. Pashure pokukwidziridzwa kuva kaputeni, Crabtree akatumirwa kwenguva pfupi kuCentral Asia asati asiya uto. 