The UK's capital gains tax hike aimed to boost government revenue, but the result was counterintuitive. Tax collections actually dropped by 18% as high-net-worth individuals relocated abroad, taking their taxable gains with them. This case illustrates a fundamental principle in fiscal policy: aggressive tax increases can trigger capital flight, ultimately reducing total tax revenue rather than increasing it. Without proper market behavior analysis, policymakers risk creating unintended economic consequences that contradict their original objectives.