Originally Posted by
layz
That's illegal, although there's a common travel area you're still not supposed to enter the UK without the appropriate documentation even if you could go to Ireland and get through to the UK that way.
While I'm not an immigration expert, my reading of the
legislation and the
Immigration Rules is that it wouldn't be illegal since the OP is not a visa national and doesn't
require a visa to enter the UK simply because he's been refused entry before. (He may want to apply for a visa for peace of mind, but doesn't require one.)
The way I read it, if he is lawfully given leave to enter the ROI and does so,
having been honest about his intentions when asked at the border, he is permitted then to travel to Belfast and onto the UK. In essence the onus is on the Irish immigration authorities to satisfy themselves that OP is entitled to enter both ROI and the UK. If the Irish border officials are not so satisfied, they should deny him entry to ROI. Similarly a UK border official can deny entry if not satisfied that the entrant has the right to enter ROI - see ground for refusal 4
here.
He might be able to get away with it, he might even get away with it just flying DUB-LHR and skipping out Belfast but in this situation the last thing you want to do is get into further trouble with the UK authorities.
If he were not entering ROI he would then be acting illegally. But provided he has been given leave to enter ROI and been honest in doing so, then
Article 3(1)(a) of the Order would not apply and so again, I think he should be ok.
Happy to be corrected by the experts on this though if I've missed something.
Also on the other question as to whether the UK authorities share previous refusal history with the ROI authorities, I don't know.