Some commentators are unconvinced that US-based multinationals with UK operations can legitimately claim not to be taxable in the UK on the full amount of their UK sales. This article is an attempt to demonstrate that they can, using a discussion of a case study, in which Irishco and UKco are both members of a US-owned technology group, and Irishco has entered into a service agreement with UKco for UKco to promote the product to UK customers. Whilst an instinctive ‘common sense’ reaction might be that Irishco’s profit on the sales activities should be located in the UK for tax purposes, the different outcome in law nevertheless accords with common sense. To the extent that UKco is contributing to Irishco’s profits, it should be properly paid for it and taxed on any resulting profit.