Corporation tax was one of the most active policy areas under the coalition government in power in the UK from 2010 to 2015. In attempting to fulfil an aim to create ‘the most competitive corporate tax regime in the G20’, the government reduced the main rate by 8 percentage points, introduced a Patent Box and reformed the taxation of foreign income. The government also made changes to the tax base – notably, reducing the generosity of capital allowances for plant and machinery and temporarily increasing the generosity of the annual investment allowance – and took steps to reduce avoidance opportunities. This paper reviews the policy changes and sets out where they leave the UK corporate tax system.