Three, better known Hong Kong
Three have never made profit in Ireland, outsource everything, mis-advertise. Mis-represented their bid for Irish national Broadband Scheme (they won and the closest they got to supplying Broadband was satellite). Also was in breech of licence conditions till they won NBS (not enough coverage). Yet ONLY concern of Regulators of O2/Telefonica Ireland & later UK take overs was "competition" and thus price.
Price should NOT be the sole criterion of having a licence for such a rare, limited and important thing as Mobile Licence. Vital National Infrastructure.
ALL mobile spectrum should be operated by a single company and everyone else be MVNOs. Also PROPER quality based regulation, not just "price".