This Practice Note explains how profits attributable to a non-UK resident company’s UK permanent establishment (PE) are taxed and collected for the purposes of corporation tax. If the non-UK resident company is resident in a territory that has a double tax treaty (DTT) with the UK, the UK’s domestic legislation on profit attribution must be considered alongside the provisions of that treaty. This is because the terms of a DTT (i) can reduce or eliminate a tax liability calculated under domestic law, but (ii) cannot increase a tax liability calculated under domestic law or impose a tax charge where one would not otherwise exist under domestic law. This means that, generally speaking, if UK domestic law results in a higher tax charge than under an applicable DTT, the treaty prevails, but if the treaty results in a higher tax charge, domestic law prevails. For guidance on the definition of a PE, both under the UK's domestic legislation and under treaty law, see Practice Note: What is a UK permanent establishment? Note that the UK domestic