The scope of negligence liability of public authorities in English law has undergone significant changes in the Post-World War II period, first expanding and then, from the mid-1980s, retracting. This article tries to explain why this happened not by focusing, as is common in most commentary on this area of law, on changing doctrinal “tests,” but rather by tying it to changes in the background political ideology. My main contention is that political change has brought about a change in the law, but that it did so by affecting the scope of the political domain, and by implication, also the scope of the legal one. More specifically, I argue that Britain's Post-War consensus on the welfare state has enabled the courts to expand state liability in accordance with emerging notions of the welfare state without seeming to take the law into controversial territory. When Thatcher came to power, the welfare state was no longer in consensus, thus making further development of legal doctrines on welfarist lines appear politically contentious. The courts therefore reverted back to older doctrines that seemed less politically charged in the new political atmosphere of the 1980s.