A former head of the Northern Ireland Civil Service has said some form of Irish unity is not unthinkable in principle.
Sir Kenneth Bloomfield added, however, the idea of closer association would also have to be mutually acceptable in practice.
He told the 40th anniversary Merriman summer school in county Clare: "Please do not suppose that if, in some future poll, 50.1 per cent of the electorate were to vote for Irish unity, the outvoted 49.9 per cent would tramp into the new jurisdiction like a defeated army."
Sir Kenneth, who earlier this year published a book called A Tragedy of Errors: The Government and Misgovernment of Northern Ireland, said successive Stormont governments had been too slow to acknowledge the Irishness felt by an "extensive minority" in Northern Ireland.
The former Victims Commissioner, currently involved with the Independent Commission for the Location of Victims' Remains, said Irish unity should be thought of as a possible or potential contract between distinct groups of people "with all the cards on the table."
It would not be a single step but a process with a "modest beginning and no predetermined end," he told the gathering on its 40th anniversary.
"So it is that I do not find the idea of some form of Irish unity or closer association - almost certainly after my time - in any way unthinkable in principle," Sir Kenneth, who was secretary to the 1974 Sunningdale power-sharing government, said.
"But what is conceivably acceptable in principle would have to be mutually acceptable in practice."
Stressing he was offering a personal perspective, he added: "As I grow older, I care less which flag is flown and which anthem is played where I live."
Sir Kenneth, who was targetted by the IRA in a bomb attack on his Co Down home in 1988, said he accepted the presence in government of Sinn Fein.
He said he would find it difficult to bear "with any sense of self respect" any relapse into a period of " that parody of democratic government, direct rule".
"Far sighted politicians, economists and academics will have to think long and hard about the true nature, cost, ethos and dynamics of a new orientation of affairs," he added.