Speeches were given by ministers, activists crammed into overheated meeting rooms, panels were under way on all manner of topics. Yet 24 hours after the journalist Charlotte Edwardes made an explosive allegation that Boris Johnson had inappropriately grabbed her thigh, the Conservatives were still dealing with that revelation by trying not to talk about it.

Cabinet secretaries stuck to scripts about “getting Brexit done” and the opportunities for the country after leaving the EU, but at event after event politicians were asked by journalists to give their thoughts on the alleged incident, which Edwardes says took place 20 years ago at a lunch when Johnson was editor of the Spectator.

A terse Nicky Morgan – the culture secretary and one of the Tories’ most senior women – said at one fringe event: “The prime minister’s spokesman has been very clear. There is no truth in these allegations. I have no further comment to add.”

Just an hour earlier she had been asked the same thing. The journalist’s question was met with groans from activists, clearly irritated the story had run into a second day.

The housing minister, Esther McVey, questioned whether the alleged incident happened. “What I hear is he’s categorically denied that and usually Boris doesn’t really say too much about anything, so I think you need to go back and check whether it did happen,” she said.

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One minister said in a private meeting that Johnson’s alleged “pinching of a knee” – Edwardes claimed it was her inner thigh – was “priced in” by voters and they did not think it would damage him in the long term. However, on the conference hall floor, activists were concerned about how the negative press about the prime minister and his relationship with women would play out.

Annabel Tall, the Conservatives’ prospective parliamentary candidate for Bath, said: “He hasn’t been charged, he hasn’t been found guilty. Someone could brush against my shoulder now. My interpretation can then lead to people making huge value judgments. People are making a huge value judgment now about unsubstantiated allegations. If this has happened to this woman it needs to be taken very seriously.”

Tall added: “The timing of this makes me uncomfortable. Why not mention anything for 20 years and bring it up now? The timing of it makes it look like it’s politically motivated.”

About the possible long-term effect of the alleged incident, Michaelene Holder-March, the founder of the BME small business group for the Conservatives, said: “When you look at the Conservative party there’s no doubt about it, we have a lot of females in leadership, including Theresa May, and coming out with this at this time – it’s to undermine the whole ethos and where we are going. It seems people are searching for a reason to undermine the party at the moment.”

Tall said she was worried it might have a longer-term impact among female voters. “It’s so divisive. People start to make value judgments. It probably will have a damaging impact.”

However, Toby Young, an associate editor of the Spectator, laughed off the allegation. He told an event at conference: “Back then at the Spectator, in those raucous days, people complained if Boris didn’t put his hand on their knee. Times really have changed.”

Fatigue among activists with questions about Johnson’s personal conduct set in by mid-afternoon. When the Mirror’s political editor, Pippa Crerar, asked if Johnson was responsible for the coarsening of political debate using words such as “surrender” and “betrayal”, and for mentioning the murdered MP Jo Cox in the context of Brexit, she was booed by the crowd.

Johnson has strenuously denied the incident happened and continued to tour receptions at conference as planned. At the private Women 2 Win event, to encourage women to stand as Conservatives, he was met politely at the door by the co-founder Anne Jenkin.

He got laughs and cheers from the crowd when he said: “At an election, whenever that happens, I want to see more women elected to parliament. When I ran City Hall it was virtually a feminocracy.”

Pointing to his former deputy Victoria Borwick, he said: “Victoria, my wonderful deputy mayor, can testify to that.”

However, not all activists were agitating to move the debate on or dismiss Edwardes’ allegations out of hand. One Tory member said they thought the revelation could be the tip of the an iceberg.

He said: “There will be more to come. I’m surprised this didn’t come out during the election period.”