This paper documents some stylized facts on evolving UK Phillips curves, and shows how these differ from their US versions. We interpret UK Phillips curve dynamics in a positive theory of monetary policy---how policy-maker attitudes on the Phillips curve have evolved since the 1950s---rather than, more traditionally, as interaction between exogenous demand and supply disturbances. Combining this framework with reasoned conjectures on how policy-makers' beliefs have changed helps explain some features of the evolving UK Phillips curve. We suggest that correlations suggesting an extreme favorable unemployment-inflation tradeoff might indicate not something to be exploited but instead only policy-makers' correctly acknowledging that no tradeoff exists.