"I checked carefully that the sign stated that British Nationals could bypass Irish immigration"
Christep...with all due respect, but none of the Immigration signs at Dublin airport say that, Signs are marked "EU Citizens" & "Non-EU Citzens"
But even at that, I do admit that the signage at Dublin is very poor and gives the impression that it was put together by a 5 year old, who ever is in charge of Immigration at Dublin should get a kick in the pants and bring the Immigration areas and signage into this century. The immigration area at Pier A is a disgrace, Pier B looks like a second world airport and Pier C ic too small when TransAtlantic flights arrive each morning circa 1000 and PAX are mixed with European and UK flights