Three seems to be making headway with abolishing roaming charges for Irish roaming customers. Hearld AM reports

Under the terms of the scheme, Three customers visiting Britain Italy, Austria, Australia, Hong Kong, Sweden and Denmark will no longer be charged for receiving calls and texts. Customers can also use existing minutes, text and data bundles to make voice and video calls, send texts, picture and video messages, and even surf the internet.

Update:
This shocked me, Meteor is Irelands biggest network when did that happen, i though it was Vodafone? (source again Hearld AM):

Three has 14 million customers worldwide, but refuses to release numbers for its Irish operation, where it is believed to have fewer than 50,000 subscribers, compared with 750,000 for the next biggest network in Ireland, which is Meteor.