In 2012, Home Secretary Theresa May told a newspaper that she wanted to create a ‘really hostile environment’ for irregular migrants in the UK. Although the phrase has since mutated to refer to generalised state-led marginalisation of immigrants, this article argues that the hostile environment is a specific policy approach, and one with profound significance for the UK’s border practices. We trace the ‘hostile environment’ phrase, exposing its origins in other policy realms, charting its evolution into immigration, identifying the key components and critically reviewing the corresponding legislation. The article analyses the impact and consequences of the hostile environment, appraising the costs to public health and safety, the public purse, individual vulnerability and marginalisation, and wider social relations. We conclude by identifying the fundamental flaws of the policy approach, arguing that they led to the 2018 Windrush scandal and risk creating similar problems for European Economic Area nationals after Brexit.

2012年，内政大臣特蕾莎·梅（Theresa May）对一家报纸表示，她希望为英国的非正规移民创造一个“真正的敌对环境”。尽管此词后来变了词，指的是由国家主导的普遍性移民边缘化现象，但本文认为，敌对环境是一种特殊的政策方法，对英国的边境惯例具有深远的意义。我们追踪“敌对环境”一词，揭示其起源于其他政策领域，描绘其演变为移民的过程，确定关键要素并严格审查相应的立法。本文分析了敌对环境的影响和后果，评估了公共健康和安全，公共钱包，个人脆弱性和边缘化以及更广泛的社会关系的成本。