s 270CC Foreign permanent establishments
A business carried on through one or more permanent establishments outside the United Kingdom by a company in relation to which an election under section 18A of CTA 2009 (exemption for profits or losses of foreign permanent establishments) has effect— (a) is an activity separate from any other activity of the company, and (b) is to be regarded for the purposes of this Part as an activity all the profits and gains from which are not, or (if there were any) would not be, chargeable to tax.