Ireland and the UK may be facing their last chance to "save the opportunities for reconciliation" created by the Belfast Agreement, Fianna Fáil leader Micheál Martin on Saturday.
In a speech critical of both political and economic failings in Northern Ireland, Mr Martin suggested the creation of a "special economic zone" which could allow for alternative trading relations in both domestic and foreign markets.
"Whatever way you look at relations within these islands, the simple fact is that we either radically alter the current path of behaviour or deep and lasting damage will be done," he told a meeting of the British Irish Association in Cambridge.
“There are specific crises in hand which have to be urgently addressed but they are part of a wider pattern which will keep going unless we act.”
Mr Martin, a former minister for foreign affairs, said in the past one of the core reasons progress was a chieved was the priority given to the relationship between Dublin and London.
However he lamented a 2011 decision to let the parties “get on with things” . “In Dublin there was an explicit stepping back from the idea that we had an ongoing role in ensuring the effective working of Northern institutions,” he said.
Mr Martin said an exception to this was during Charlie Flanagan’s period as minister for foreign affairs. “His removal from that post after such a brief and positive period remains unexplained and unjustified,” he said.
Mr Martin pointed to failings in both the North’s political institutions and economic development.
With deadlock at Stormont, he added that Brexit now threatened "genuinely historic damage", met as it was with a "limited, unimaginative and complacent response".
He said the key questions regarded “endemic poverty” in the North, credible long-term development and a reversal of sectarian entrenchment.
“I believe we may be facing our last chance to save the opportunities for reconciliation and development created by the peace settlement.”
He proposed a four-point solution, involving a return to ongoing co-operation and engagement between the Irish and British governments; the creation of a new economic model; restarting North-South co-operation in the areas of infrastructure and services; and a new bilateral treaty governing British-Irish relations.
Peace settlement
“The biggest reason that we achieved a peace settlement was the determined work of democratic politicians to find a way of getting the extremes to abandon their illegitimate campaigns,” he said. “Let’s never forget the real heroes of peace are those who, often in the face of appalling provocation, never made war.”
Regarding his proposed special economic zone, Mr Martin explained this could cover both Northern Ireland and, at least, the Border counties in the Republic. Such a model, he said, could be created while respecting the constitutional rights protected in the Belfast Agreement.
The meeting heard there were 4,500 such zones around the world, many of which created the conditions for different trading arrangements in domestic and international markets.
“A special economic zone in Northern Ireland could be recognised by the EU as being distinct from the rest of the UK in terms of single market and customs union access,” he said.
