SolvedDT9882 | Double Taxation Relief Manual: Ireland: dividends
From HM Revenue & Customs · Double Taxation Relief Manual
A United Kingdom resident recipient beneficially entitled to a dividend from an Irish company will pay the following reduced rates of Irish withholding tax:
Under the UK/Ireland treaty, 5% if the recipient is a United Kingdom resident company not within the above, but controlling directly or indirectly 10% of the voting power of the Irish company
all other cases: 15%.