The UK officials cited the Berlin Wall as inspiration for a highly controversial barrier, according to an Irish memo now released to the public.
British forces were struggling to regain control in border regions during the Troubles and proposed establishing posts along the entire length of the border at the time.
The Republic of Ireland responded with fury to the suggestion, according to the 30-year-old memo from Irish official Noel Ryan.
He said Dublin was stunned at the British proposal during a meeting between the Irish Department of Foreign Affairs and a team of UK officials.
The memo detailed British complaints at the difficulty of dealing with IRA activity in the border areas. Dublin also strongly condemned British Army incursions across the border into the Republic.
Mr Ryan’s notes said: “Drawing on examples from recent years, we reminded the other side of the degree of seriousness with which incursions were regarded in the South and their capacity for generating political controversy.
“[The British said] their best efforts might not be sufficient to reduce significantly the occurrence of incursions, given the nature of the terrorist threat, the intensive security operation required to meet it, and the lack of clear physical delineation along the lengthy border.”
It was then the UK discussed the possibility of an Irish border wall – a move which would have been incredibly inflammable given Dublin’s claim at the time to Northern Ireland.
It would also have proved difficult given the winding nature of the Irish border, which divides towns, farms and even some properties.
Mr Ryan wrote: “The second idea under consideration on the British side was the possibility of physically delineating the Border along its full length.
“They cited, as an example, the frontier between East and West Germany which is delineated by posts set in the ground at regular intervals of five metres or so.
“We responded in very strong terms to this idea, arguing that it was unthinkable that it should ever be put forward seriously, and that if it emerged publicly, in any form, the impact on Anglo Irish relations would be disastrous. The British took these points on board.”
The proposed border wall was never built but many roadblocks and checkpoints nonetheless caused chaos and controversy during the Troubles.