These parties’ extremist tendencies and narrow platforms are limiting governments’ policy flexibility by driving relatively moderate parties and politicians to adopt more radical positions. It was concern about the United Kingdom Independence Party’s capacity to erode the Conservatives’ political base that pushed Prime Minister David Cameron to commit to a referendum on the country’s continued EU membership.
这些政党的极端化倾向和狭隘的平台促使相对温和的政党和政客不得不采取更加激进的立场，从而限制了政府政策的灵活性。有人担心英国独立党（Independence Party）有能力破坏促使首相卡梅伦决心就是否保留欧元区成员地位问题举行全国公投的保守党的政治根基。