Alliance Party leader Naomi Long casting her vote last Thursday

Recognising the unique opportunity which a Northern Ireland-wide single constituency provided a charismatic and media-friendly candidate, he dominated European elections long before his party dominated politics.

But where Paisley harnessed unionist voters’ intrinsic fears, the Alliance leader’s victory is more remarkable because of her centrist message.

For any party to more than double its highest ever European election vote in the space of five years is almost unthinkable.

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The scale of Alliance’s victory is quite without precedent since the start of the Troubles half a century ago. Whereas Alliance’s surge in the council elections earlier this month – where it took 11.5% of the vote – did not bring it back to the 14.4% of the vote which the party had 50 years ago, this result of 18.5% shatters that ceiling.

Prior to the Troubles, the old non-tribal Northern Ireland Labour Party took 25% of the vote in the 1962 Stormont election before being squeezed out as the Troubles began.

Mrs Long was helped by the way in which the unionist parties were bunched up in the same territory on the issue central to this election: Brexit. There was simply no unionist candidate for a pro-Union but pro-EU voter to endorse without having to choose between those two ideologies.

One voter, a former Ulster Unionist member, said on polling day that he was voting for a “pro-Remain party” – quite possibly Alliance.

But his reason for doing do shows the danger of assuming that voters who move from unionist or nationalist parties are suddenly neutral on the border. His move away from a unionist party was, he said, because of his view that “all the ‘unionist’ candidates hold a position that risks the integrity of the UK”. Far from his vote for a non-unionist being an abandonment of his unionism , he voted out of his belief that it was the best way to save the Union.

That runs contrary to widespread unionist messages that a vote for Alliance is somehow a threat to the Union – a message which it has for years been clear does not resonate with voters.

Five years ago, the total pro-Union vote was 52.6% — spanning from Ukip to NI21.

NI21 imploded amid chaotic in-fighting. But yesterday senior figures from the DUP and UUP – some of whom would never vote for such a party – privately discussed the need for an NI21-type liberal pro-Union party if unionism is to reconnect with the zeitgeist.