The Laffer Curve begins with an observation so simple that it is difficult to dispute. Change the tax rate and people change their behaviour. Identify wealthy taxpayers, determine how much they earn or own, increase the tax rate and announce how many billions will flow into Treasury. More importantly, if increasing someone’s tax rate discourages investment, encourages restructuring or causes the taxpayer to leave, what has been achieved? The tax rate that maximises government revenue is not necessarily the tax rate that maximises national prosperity.