So the CTA is not as polemic to the Irish as certain parts of the British state? IS that fair to say? I can't begin to imagine the world of pain if they were to introduce document checks to get into Britiain from Ireland. Thanks for that, did not know this was a requirement.
I don't think checks in practicality would be a major problem at all considering how advanced technology is. E-Gates could do the job for the vast majority of passengers traveling between IE-UK if Irish flights had a few dedicated at each airports and programmed to clear Irish/British ID holders only.
Checks for NI passengers entering mainland airports wouldn't go down well and it would be pointless for checks form DUB and not BFS people could just cross border and enter if they want to avoid checks.
If you look back to 2008 UK Border Agency published a paper to have checks for Non CTA citizens, enhanced ID for CTA citizens and new advanced data system for all people traveling between both countries. Some unionist's in NI were not happy and in 2009 the House of Lords defeated it and it was again tabled by the then Home Office Minister under Public bill committee but removed after continued opposition.