Andy Burnham has caused Sinn Féin difficulties.

The British prime minister’s remark last week that a Border poll is “off the table” has been seized on by some dissident republicans as proof that the Belfast Agreement cannot deliver a united Ireland and that Sinn Féin has been naive or complicit in a peace process surrender.

Sinn Féin has never enjoyed that accusation, naturally, but nor has it ever stinted at dismissing dissidents. The party will be far more concerned by rumblings from its own base. This has been evident in social media comments from supporters and members, demanding Sinn Féin take a more assertive stance towards Burnham, unionism and advancing the republican cause. A common theme emerging from these remarks is that Sinn Féin should withdraw from Stormont, or not return after next May’s election, unless London provides clarity on a Border poll – the precise conditions for triggering a vote, for example, or a timescale, or a commitment to preparations.

Sinn Féin does not want to walk out of Stormont, yet this is a notion it has just planted in its supporters’ heads. Following a poor opinion poll result in late July, the party blamed the DUP for obstructing its policies and dropped unsubtle hints about the stability of devolution. This was only intended as a distraction from Sinn Féin’s failures in office but it took on a life of its own as other parties and the media began to speculate about a collapse.

Michelle O’Neill, the First Minister, finally had to shut the speculation down in the middle of August by declaring she had “no intention” of leaving Stormont.

On Sunday, she had to repeat the message, this time directly addressing Sinn Féin’s base. O’Neill told a hunger strike commemoration in Co Mayo: “Walking away would mean handing control of our public services over to British government ministers … that would be disastrous and Sinn Féin is not going to do that.”

In the same speech, O’Neill denounced Burnham’s comments as “arrogant”, insisted the Belfast Agreement provides “a right” to a Border poll and complained again about DUP obstruction. Her party is struggling to reconcile the promises it has made with the disappointments of reality.

Unionists have provided a new distraction by reviving the Drumcree dispute. Sinn Féin has waded in, with unionists already accusing it of stirring up tensions. This cynical electioneering, on both sides, could quickly get out of hand.

In the heyday of the peace process, whenever Sinn Féin professed difficulties, the British and Irish governments would rush to its aid.

Assistance on this occasion has been more modest, so far. Northern Secretary Chris Bryant clarified that Burnham did not mean a Border poll is permanently off the agenda. Fianna Fáil and Fine Gael ministers said their Government is working towards a united Ireland, although not through a “premature” vote, to quote the Minister for Enterprise Peter Burke. Leo Varadkar chipped in with a comment that he sees unification taking “decades”.

Andy Burnham is right. Holding a poll to test the waters on unity should be off the table

While not primarily aimed at helping Sinn Féin, such statements give the party a way out of the corner it has painted itself into by demanding a poll this decade. Leading civic voices, including the Irish News and the Sunday Independent, have called on the British government to set out its criteria for a Border poll. Both newspapers said this would provide certainty to unionists and nationalists, stabilising Stormont politics.

It could have the opposite effect. If the requirement was a nationalist assembly majority or an electoral majority it might seem so far off it could cause serious republican frustration.

Any lesser requirement would be seen by unionists as undemocratic.

Requiring a nationalist plurality, or an assembly vote for a poll, would place intolerable pressure on parties such as Alliance to declare a position, destroying the centre ground.

The courts in Northern Ireland have ruled that the Belfast Agreement deliberately left the criteria vague, as the decision is properly a matter of political judgment. Refusing to let this lie may itself be needlessly aggravating.

The best help Sinn Féin received last week came unwittingly from former British prime minister Gordon Brown. In an interview with The Guardian, conducted before Burnham’s remarks but published afterwards, he said “of course, in the long-term, Ireland will be united”.

Ireland will be united, says former British prime minister Gordon Brown

Brown’s statement has up-to-date significance because he is Labour’s elder statesman on constitutional reform, a Burnham priority. He prepared a landmark 2022 report for the party, since adopted by Burnham, on new arrangements for devolution throughout the UK. As a Scot, Brown’s imprimatur is seen as important to counter Scottish independence, yet he is still prepared to declare a united Ireland inevitable – eventually.

The hint everyone is sending Sinn Féin is to push back its absurd stated timescale for a Border poll and focus on governing Northern Ireland better in the here and now.