Technically speaking , many European countries already have "Basic Income". ( France , Sweden , Norway...) They are reserved for individuals "Not Active" though ( Unemployed and not looking for a Job ) over a certain age. Those "BI" massively lower poverty , which usually massively reduce crime-rate , drugs related usage etc... With 700€/Month you aren't gonna far anyway, you have enaugh for food and rent , and that'…
People keep forgetting that a UBI won't cover immigrants. Immigrants would end up doing all the jobs that citizens don't want to do. That's the biggest problem with UBI. It creates a default class system.
Or maybe you're talking about UBI to immigrants, but not actually allowing any immigration.