The authorities passed the Defence of the Realm Act which gave the government unprecedented powers to intervene in people’s lives.
Suspicion of outsiders was high. Non-British-born subjects had to register, obtain permits to travel more than 5 miles and stopped from entering certain areas. 32,000 were held in internment camps or repatriated.
Anti-German sentiment caused riots in many cities, particularly after the sinking of the Lusitania by a German submarine in May 1915.
An example is this report from London: The damage was especially extensive in the area near the East India Dock, where over sixty German shops have been attacked. Terrified Germans, who were found hiding under beds, were thrown out into the street, beds and all. A German piano was set up in the street and British patriotic songs were played upon it.