s 4 Link to the United Kingdom
A digital activity is linked to the United Kingdom for the purposes of section 2 (1) (a) if— (a) the digital activity has a significant number of UK users, (b) the undertaking that carries out the digital activity carries on business in the United Kingdom in relation to the digital activity, or (c) the digital activity or the way in which the undertaking carries on the digital activity is likely to have an immediate, substantial and foreseeable effect on trade in the United Kingdom.