Former DUP leader Peter Robinson has said the battle for the Union is raging and has accused critics of his border poll comments of "crass folly".
riting in today's Belfast Telegraph, Mr Robinson said those who refused to prepare for a referendum on Irish unity were burying their heads in the sand.
Too many unionists took the longevity of the Union for granted, he warned. A Labour Government under Jeremy Corbyn would likely hold a border poll and a Tory administration not dependent on DUP support might also do so, he cautioned.
"While those who are still in denial and refusing to talk about the elephant in the room, it is positioning itself to squat upon their laps," he added.
Speaking in Co Donegal last week, Mr Robinson had said unionists should prepare for the possibility of a united Ireland, even though he didn't believe it would happen. He warned them to be ready for a border poll.
His remarks were heavily criticised by the Ulster Unionists, TUV leader Jim Allister and DUP MP Sammy Wilson.
Mr Robinson hit out at what he called the "hysterical commentary" on his speech.
"Some people have suggested such matters should not even be discussed as it may provide momentum towards the very outcome we seek to avoid. Such claptrap. Where are they living?" he asked.
"This battle started long ago. Let us be very clear, contrary to what these shrill voices are saying - whether a border poll is called or not isn't in their gift."
The former DUP leader said "no amount of grandstanding changes the fact that unionists cannot stop it happening".
Unionists should be "actively getting the rules and procedures (on) a border poll and its aftermath sorted out to their satisfaction - now". Otherwise, they would be giving their opponents "a 10-mile start", he said.
Unionists mustn't listen to those who advised "it will never happen" or "don't worry, we will just wing it on the day". "Such crass folly," he continued. "These people have not just buried their heads in the sand - only the soles of their feet are visible above the surface.
"Do they not realise that the battle is raging? We live in a society divided by identity so to some extent the Union is always under fire. But surely nobody could be so chloroformed that they don't recognise that the opponents of the Union are charging our lines like seldom before. The battle for the Union is on."
The former DUP leader said that unionists "pulling a paper bag over our heads and thinking we can close out the impending danger is crazy". He continued: "They seem to believe a battle does not start until they want it to commence. They argue that talking about these matters 'aids the enemy'. Rubbish! It is inertia that 'aids the enemy'."
Mr Robinson praised his successor Arlene Foster for her "forceful and persuasive" case for the Union in a recent speech, and chided other unionist politicians for not doing the same "while nationalists and republicans have been pouring out united Ireland propaganda". The pro-Union case deserved more than "a scattergun approach" and had to be made beyond "the party faithful and the natural support base", he added.