Theresa May was halfway through a slur against Jeremy Corbyn when comedian Simon Brodkin appeared at the podium and handed her a huge P45, saying “Boris asked me to give you this”. He was bundled out to shouts of “Out! Out! Out!” from the crowd, and the prime minister made a half-funny joke and returned to her script.

She had started off well, apologising for the general election campaign and defending free market capitalism but acknowledging the role of state intervention. She recited her record of standing up for marginalised groups, telling the conference that she had gone into politics “to give a voice to the voiceless”.

Britain’s prime minister Theresa May. Her address was painful to watch, and almost impossible to listen to what she was saying rather than waiting for the next coughing fit. Photograph: Facundo Arrizabalaga/EPA

Voiceless is exactly what she became herself a few minutes later when she coughed, spluttered and coughed again. She sipped some water but it was no good, she could scarcely get a word out. The reporter next to me kept repeating “poor thing, poor thing” and then the crowd rose to give her a standing ovation, sustained long enough to give her a chance to swallow more water.

“Do you think this might be good for her? They’ve moved from respecting her to loving her,” my neighbour said.

Hi @BorisJohnson, I gave Theresa her P45 just like you asked. pic.twitter.com/gzW0UluDMv — Simon Brodkin (@simonbrodkin) October 4, 2017

But it wasn’t love, it was pity. And as the audience rose again and again with each new coughing fit, they were not acclaiming her but protecting her.

Interminable silences

Chancellor Philip Hammond gave the prime minister a throat lozenge and she joked about getting something free from the treasury. For a while, her voice returned almost to normal but then the cough was back again, choking her into what seemed like interminable silences.

It was painful to watch, and almost impossible to listen to what she was saying rather than waiting for the next attack. Then a fresh little calamity unfolded behind her as two letters fell off the slogan “Building a country that works for everyone” so it now read “Building a country that works or everyon”.

When she got to the end, the crowd leapt up, cheering and applauding her indomitability more than anything she had said. Her husband Philip climbed onstage and wrapped her in a hug as her eyes began to fill.

The speech signalled a policy shift towards more state intervention in the market, promising to build new council homes and to cap energy prices. But its primary purpose was to make the case for May remaining in Downing Street, driven by duty and by a determination to restore what she called the “British dream” of each generation being better off than the previous one.

Two MPs I spoke to afterwards said the prime minister had endeared herself to the Conservative membership, and that her message would help to start the fight back against Labour. But beyond Manchester the lasting image of the speech may be that of a lonely, vulnerable figure onstage, beset by ill fortune, determined to carry on but clearly not fit for the task.