CTM03570 - Corporation Tax: small profits relief: associated company - definition
A company is an ‘associated company’ of another company if one of the two has control of the other, or both are under the control of the same person or persons (CTA10/S25 (4). ‘Control’ for this purpose is defined as for close companies (CTA10/PART10, S450 and S451,see CTM60210).
A company may be an ‘associated company’ no matter where it is resident for tax purposes.