DT9891 - Double Taxation Relief Manual: Guidance by country: Ireland: Associated companies
Under Article 21(4), where Ireland increases for the purposes of Irish tax the profits of an Irish company on the grounds that the transactions between that company and an associated United Kingdom company have not been on an arm’s length basis, any amount included thereby in the profits of both countries is treated as income of the United Kingdom company from a source in Ireland and credit is allowable to the United Kingdom company in respect of the additional Irish tax. Any claim for relief under this provision should be referred to Revenue Policy International, Business Tax Group (see /manual/international-manual/intm161320).