They used to see Jeremy Corbyn as an unelectable throwback to the 1970s - but that was before the general election. Do Conservatives now think he could be the next prime minister?

"I am afraid I have to say yes. That doesn't appeal to me but I can see it."

Like many Conservatives who were in Manchester this week Ron Allcock is struggling to get his head round the idea of the Labour leader as a credible opponent.

"He is grabbing all the headlines and people are now thinking 'well, he isn't a bad guy after all'. It's astonishing. Really astonishing."

Image caption Ron Allcock says the party needs to do something "dramatic"

What worries the 80-year-old Chelmsford councillor is that Mr Corbyn appears to have grown in confidence since the general election and that young people still appear to be flocking to his side.

"We have to think of something really dramatic to get their attention," he says.

Everyone you speak to here admits they underestimated the Labour leader - but opinions are divided over how to fight back.

Image caption Jane Hunt and Hilary Fryers think the Corbyn bubble will burst

Some, such as Jane Hunt, whose dreams of unseating Labour's Lilian Greenwood in Nottingham South crashed and burned in June, believe the Corbyn bubble will burst.

"We need to get through the stage where Jeremy Corbyn is sexy. He is going through a phase where people think he is a Messiah almost. That will soon die off. It's built on absolutely nothing as far as I can see."

Like others you speak to, she claims Mr Corbyn "hoodwinked" young people by promising to abolish tuition fees and "sort" their debts.

"I am afraid I think the students were absolutely conned and I think they will switch off from politics once they realise they've been conned. They'll be switched off for a generation and that's really unfortunate."

It certainly cost her her own chances, she says, as students queued up outside polling stations to cast a ballot for her opponent, who got 10,000 extra votes.

Mrs Hunt's friend, Hilary Fryers, from Market Harborough, agrees that Corbynmania is "built on sand" and will eventually crumble.

Image caption Anthony Clarke says the election campaign was too negative

Some Tories - including Theresa May's Parliamentary aide George Hollingberry - believe it was a mistake to attack Mr Corbyn on his record at the general election.

"It's not good just harping back to the 1970s, talking about Hamas, trying to do Jeremy Corbyn down, there's a message out there that people are listening to and we've got to tell them why it's dangerous, why it's wrong for the country and why they shouldn't fall for it," he told BBC Radio 4.

Anthony Clarke, the election agent for former Bath MP Ben Howlett, who lost his seat to Liberal Democrat Wera Hobhouse in June, says many Tory voters were turned off by the relentless attacks on Mr Corbyn's character.

"You could argue that we would have done much better if we ignored him, sidelined him," he says.

Image caption Diana Beech says Corbyn's polices need to be 'unpicked'

But he has his doubts about whether the Labour leader will ever walk through the doors of Number 10.

"He is potentially quite a difficult opponent, for one reason or another. I still don't rate him as somebody who is capable of ruling this country.

"When we have got Brexit out of the way and everything has settled down I don't think he will be in that position."

One thing everyone does agree on is that the party urgently needs to do more to attract younger voters.

"I think there is such a momentum growing out there, to coin a phrase", says Diana Beech, director of policy and advocacy for the Higher Education Policy Institute, and a Conservative Party member,

"People feel disillusioned. They want change. I just think there is a growing momentum from the grassroots, helped by social media."

But she does not think the party should try to ape Jeremy Corbyn's policies.

"I think the only way to bring it down is to unpick the economic arguments."

Josh Rendall, of Chelsea and Fulham, pictured above, agrees.

"The party didn't appeal to under-40s at the last general election. There was no overall vision.

"What the prime minister has done this week is a good step forward but having Labour-like policies, I don't think really works for anyone."

As for Mr Corbyn, he says: "I personally underestimated him.

"Just look at his conference speech last week, compared to the one a year ago or even two years ago. He was a man who had confidence, he wasn't flailing about. He was confident in himself and I think the party underestimated that."

The Conservatives need better policies on housing and student finance, not just watered-down versions of Jeremy Corbyn's policies, he argues, in what is becoming an increasingly familiar refrain at this conference, "but I don't know what they are".