Much recent analysis of British politics has assumed, explicitly or implicitly, that constituency campaigns have no impact upon an electorate that draws on an increasingly nationalized media for its information. We employ data on constituency campaign spending to challenge this interpretation. Local party campaigners are rational in their use of funds, spending most in seats where the competition is close and least where there is little hope of winning. What is more, campaign spending is clearly associated with voting, increasing support for the spending party and decreasing support for its rivals. Contrary to the accepted wisdom, local campaign spending can result in important shifts in the vote. However, local campaigning seems to be of much more value to challengers than to incumbents.