No one foresaw the extent of this Sinn Féin surge.

Not even Sinn Féin.

I asked a senior party strategist and number cruncher shortly after the polls closed at 10pm on Thursday for his predicted number of seats.

"The feedback on the doorsteps has been very good and I think on a good day we could gain 20 to 25 seats," he replied.

The actual gain since the last local government elections in 2019 was 39, taking the party to 144 seats across Northern Ireland's 11 councils.

144 elected councillors from a total of 162 candidates.

Having finished 17 seats behind the Democratic Unionist Party (DUP) four years ago, the party is now 22 ahead.

It even managed to pick up seats for the first time in traditionally unionist strongholds like Ballymena and Coleraine.

The DUP certainly did not see it coming.

Senior party sources had conceded in advance that they expected Sinn Féin to emerge as the largest party in local government based on its performance in the Assembly elections last May, when it emerged as the largest party at Stormont for the first time.

However, the facial expressions and body language of senior party members at the Belfast count centre yesterday suggested a sense of shock.

On another day the story would have been the continued growth of the centre-ground Alliance Party, which has now leapfrogged the Ulster Unionists and the SDLP to become the third largest party in local government.

But THE story was the continued surge of Sinn Féin.

Read more:
Sinn Féin is the largest party in Northern Ireland's local government

The party, with desires of being in government in the Republic, is now the dominant electoral force north of the border.

One of the key factors in its success was undoubtedly the continuing DUP boycott of power-sharing at Stormont.

While the DUP insists the policy is solely about its campaign against the Northern Ireland Protocol, and its successor the Windsor Framework, the reality is that many nationalists simply do not buy that.

Many, including those who did not traditionally vote Sinn Féin, interpreted the move as a deliberate strategy to block or at least delay the appointment of Michelle O'Neill as the first Catholic and nationalist First Minister of Northern Ireland.

"I’m not surprised. It was very clear to me that people, particularly nationalists, wanted to come out and reassert that result from last year, they were very extremely annoyed that Michelle O'Neill has not been able to become First Minister," said SDLP leader Colum Eastwood.

The DUP focus on the constitutional issue and the need to restore Northern Ireland’s "Britishness" throughout the past year was also a factor.

It will be a case of "go raibh míle maith agat Jeffrey, as Sinn Féin celebrates its spectacular council election success," is how Suzanne Breen, the Belfast Telegraph’s Political Editor put it.

Sinn Féin mauled its nationalist rival, the SDLP, in a number of councils, but it also made gains at the expense of all other parties and Independents, with the exception of the Traditional Unionist Voice (TUV).

Commentators and political opponents have referred to the "Sinn Féin juggernaut" and the "Sinn Féin tsunami."

Undisputed leader of unionism

But the big Sinn Féin win did not mean the DUP lost.

The party’s first preference vote was only marginally down, and it returned with 122 councillors, the same as in 2019.

A predicted surge by the TUV, led by former senior DUP member Jim Allister, which has taken a much harder line on any possible resumption of power-sharing, did not materialise.

The party won nine seats, an increase of three but not enough to worry the DUP.

DUP leader Jeffrey Donaldson was keen to point out that his party had consolidated its position after a year of intense pressure from across the political spectrum and governments in London, Dublin and Washington.

With the Ulster Unionist Party suffering badly, the Lagan Valley MP can say he is the undisputed leader of unionism and that he has the trust of the vast majority of the unionist electorate.

That could potentially result in him digging his heels in further and refusing to budge on his Stormont boycott.

However, the growing sense is that he is more likely to use this renewed mandate as a springboard to wring further concessions from the British government on the Windsor Framework to pave the way for a return to power-sharing, most likely in the autumn.

Having seen off the TUV in the Stormont Assembly election and local government elections, Jeffrey Donaldson no longer has to look over his shoulder at a potential electoral threat.

"It’s a question of when we go back and not if," said a senior DUP source.

"The government knows what we need and is moving in that direction," they added.

The British government last week signaled that it is committed to "providing exactly the protections that Mr Donaldson referred to."

That’s understood to be a reference to new legislation to strengthen Northern Ireland’s position within the UK internal market.

The DUP leadership could sell that to its support base as a restoration of Northern Ireland’s full constitutional position within the UK, which it has argued was weakened by the post-Brexit trade deal.

Three party state

There are a number of takeaways from this election.

One is that, combined with the Assembly election results of May last year, there is a major realignment of politics north of the border.

It now appears to be heading inexorably towards a three party state with Sinn Féin, the DUP and the Alliance Party emerging as the dominant blocks.

The SDLP and Ulster Unionist Party are increasingly fighting an uphill battle for relevancy while other smaller parties like the Green Party, People Before Profit and Aontú are currently struggling to survive.

It is also clear that a continued DUP boycott of Stormont is likely to further energise and galvanise the nationalist and republican electorate and strengthen Sinn Féin’s position further.

That would further fuel debate about a border poll and whether the best alternative to devolution would be a united Ireland rather than direct rule from Westminster.

Michelle O'Neill is already calling for the British-Irish Intergovernmental conference to be convened as soon as possible to discuss next steps.

"Stability favours unionism," said one seasoned DUP councillor.

"Instability undermines unionism and invigorates nationalism. The only way to get back to stability is to get back into Stormont and try to make this place work. If we don’t do that, in the long term we’re weakening the union," they added.