Labour conference speeches can be notable for their omissions – as Ed Miliband found with the deficit. This year, Keir Starmer’s speech will have another significant absence – the name of Jeremy Corbyn.

Starmer’s aides confirmed Wednesday’s speech, which will definitively break with the 2019 manifesto, will not mention the previous leader by name – “Don’t mention the Corbs,” as one observer put it. Another word is also missing – “unity.” Starmer’s aides have been explicit that word will be replaced with “winning.”

Labour conference feels definitively split into two very different tribes. Five minutes walk through the Brighton backstreets towards Momentum’s The World Transformed (TWT), Corbyn himself held audiences rapt with speeches on the “war on terror” and the climate emergency – with barely a mention of the Labour party or Westminster politics.

Throughout the week, there has been unsavoury infighting and the shock resignation of shadow employment secretary Andy McDonald. But by the end of the conference, Starmer hopes to have set Labour on a very specific direction – and that means away from the crowds in the big top and facing the country.

Symbols are everywhere. In the buildup to Corbyn’s speeches, the Labour leader was often flanked by young, diverse new members. At one point in the conference hall, Nick Thomas-Symonds hailed the chair of Police Federation sitting in the audience – the first time the group has attended in more than a decade. It hammers home the message of facing outwards.

But left-wing backers of Starmer feel betrayed. That feeling has only grown as Starmer tore up Labour’s leadership rules and backtracked on nationalisation.

On Tuesday, the former Momentum national organiser Laura Parker, whose face was on Starmer’s leadership leaflets, spoke out for the first time to the Guardian. “There are 40% of the membership who voted for Jeremy twice and then for Keir. They were united around his pledges,” she said.

“Now any efforts towards party unity are absolutely blown up, it is dead in the water. I can’t believe there’s a single one of that 40% who doesn’t feel like me, totally totally despairing and actually quite angry.

“Why would you do this to your own supporters? Is it get with the programme or go away? And if it is, then what is the programme?”

Starmer’s most senior advisers say the strategy for the conference has been long in the making – and the impetus has come from the leader himself. Sources close to him say he was explicitly elected on a pledge to return Labour to power, restore trust and face outwards to the voters.

For those invested in that project, party unity means being fully on board with those aims and Starmer is not prepared to pander to those where that is not their first aim.

Starmer’s allies say he has shown iron resolve in the run-up to conference and firmly rejected any suggestion that the decision to change the party’s internal rules was not his own.

“Everything that Keir has done this week has been about giving us the best position possible to look credible to voters. Raising the leadership threshold to 20% – it shows you have firm support within the party, you can build a shadow cabinet, you aren’t at risk of being destabilised,” one senior source said.

“We freed MPs from the trigger ballot process where they spend the run-up to an election wooing their members. And we can also turn our conferences into outward-facing events. And next year – ahead of an election – we do not have to do anything of this nature again.”

Those who were running the numbers on the final day before Labour conference told Starmer they believed he would win by 50.1% without more union backing.

“Keir said he would do it, even when everyone else was losing their nerve and telling him to pull back,” one said. In the hours before the vote, Unison swung behind and made the win comfortable.

Given the pro-Starmer results on conference floor, senior Labour figures will make the argument that the majority of the membership back his direction – they are tired of losing. But the votes have not always gone the leadership’s way – on Tuesday members backed the GBP15 minimum wage.

Parker said that the treatment of the membership would start to affect Labour on the ground if there was no attempt at any outreach. “We get that you need to go to Blackpool to campaign, not just address Vauxhall CLP,” she said. “But the people paying the train fare and going to hand out leaflets with you have been treated with utter contempt.”

At TWT, so far there is a still a resolve to keep on the fight for a socialist future, bolstered by a buzz around the new generation of left-wing MPs elected in 2019. Their most promising hope is Zarah Sultana, the 27-year-old MP for Coventry South, who hosted a lively pub quiz. That event had been run in previous years by Ed Miliband.

But Corbyn himself remains the star – and similarly the name of his successor is rarely on his lips. In one official fringe event, entering the room to a 2017-style rendition of ‘Oh, Jeremy Corbyn’, the former leader mainly discussed efforts to ban fire and rehire, but quizzed about Starmer’s record as his replacement, Corbyn pointedly refused to give personal criticism.

Corbyn’s own status remains in limbo – a party member but the whip suspended. Though the situation is embarrassing, in practice it rather suits both sides. Present but not involved.