We are only a few seconds into our interview with communities secretary Sajid Javid when his irritation at the way the Tories ran their general election campaign earlier this year becomes apparent. Rather than strengthening her mandate, Theresa May’s decision to go to the country backfired appallingly, stripping the Conservatives of their Commons majority and leaving the government, in which Javid is a big player, terribly weakened.

He describes the result as “disappointing”. But such understatement cannot hide what he clearly believes was a disaster that resulted from catastrophic misjudgments by May and her campaign team at every turn. For him the awful result was all the more difficult to take because the omens from local elections just three weeks before had been so good.

“For us, it was the best set of results ever in county elections in terms of the number of councillors and councils we took control of, and even in the metro mayoral elections – four of them Conservative, including [unexpected wins in] the West Midlands and Tees Valley. They were a very good set of results, yet three weeks later we have the general election, a lot of the same people voting, but a very different and, of course, disappointing result. What was it that worked so well just three weeks before?”

Javid does not seek to defend the national campaign at all, nor the prime minister. It was too focused on Brexit, he says, and not enough on more immediate issues that mattered to people. “In the local elections, for example, we left many of our local councillors and campaigners to come up with their local manifestos and focus on the core message of what you could expect from a Conservative council – costing you less, giving you more, backing their community and businesses. That worked well.

“When it got to the general election, in some ways we almost went off message. For example, looking back, we should have talked much more about the economic change we’ve seen in the country in the past seven years – record number of jobs, lowest claimant count in over 40 years, record number of businesses.

“While we were banging on about Brexit, a lot of people were saying, ‘OK, I get that, I know you are going to deliver on Brexit, I know it is not straightforward, but what about housing? What about education? What about transport? What about the health service?’ ”

The cult of personality that was created around May also seems to have grated, misjudging what people want from politicians in election campaigns. The Tory battle bus was emblazoned with the words “Theresa May for Britain” and local candidates were hidden from view, prevented from meeting the media. None of it worked. “When people go to vote still in Britain, they will look at their local representatives, but I don’t think there is a sort of cult of personality politics. Obviously, they want to know who the leader is for each party, but I think there is a lot of identification with their local candidates.”

Theresa May arrives in Manchester for the Conservative party conference. Photograph: Oli Scarff/AFP/Getty Images

Other big figures in the party should also have got more of a look-in. “I think they like to see the presentation of the team behind the delivery if they are elected,” says Javid.

As Conservatives gather for their conference in Manchester, Javid is clearly not living in fear of May. Deference to such a weakened leader has gone out of fashion, even among the big hitters in the cabinet. It is pretty much open season now and, like many senior Conservatives, Javid knows the party is in serious trouble. It must do more to attract younger voters, most of whom cannot even bring themselves to consider voting Tory these days.

I think there is a real possibility that Jeremy Corbyn can win … look at how close he got in June

He comes very close to suggesting the Tories are losing touch with them and clearly fears that Jeremy Corbyn’s anti-capitalist rhetoric may be striking a chord. “Let’s say they were teenagers in the financial crisis 10 years ago and now they are starting to vote. Their political consciousness is maybe [emerging] during the time of the financial crisis and they hear a lot of negative stuff about the banking system and markets, and all of a sudden they are told nationalisation is the answer. They don’t remember or relate to what happened in the 1970s.”

Javid is already thinking about the next election, in a way that makes it possible to imagine him emerging as a leadership candidate. He has three priorities for boosting Tory support: “By the time of the next election, in terms of where we need to increase our appeal the most … it’s got to be in London, it’s got to be with younger voters and it’s got to be with ethnic minority voters. Those are three of the most important areas. We clearly didn’t do enough [last time].”

In his own policy area, he wants to do more to help young people and renters find decent homes and describes the lack of affordable housing as the “biggest barrier to social progress in our country today”.

On Sunday, in his speech to conference in Manchester, Javid was expected to make a series of announcements about strengthening the rights of people who rent, including requiring all landlords to join a redress system that allows tenants to complain. It will be a legal requirement that will see bad landlords sanctioned. He will also force letting agents to be registered with a professional body and meet certain minimum standards. Plans to give renters a minimum tenancy of 12 months are also being worked on.

Following the Grenfell Tower tragedy, Javid has been criticised by some community leaders for failing to do more to improve safety. But he is adamant that is he doing what he can, and is determined to make sure that residents’ concerns are listened to, respected and acted upon in future. As the public inquiry gets under way, he wants answers. “The residents there were not listened to. Why did that happen? How could it have gone on for so long [that it] led to this absolutely horrific tragedy?”

There are wider issues here for all people in positions of authority. “I do think there are some big questions here about approach, about how people are treated. I was brought up in very challenging areas. I used to live in a street in Bristol which was, depending on your tabloid of choice, either Britain’s most dangerous street or a moral cesspit. People made judgments about me on where I lived. It affected me – it affected my life chances. That is going on today with people in social housing. That to me isn’t acceptable.”

We are running out of time and Javid is in a hurry. We have a couple of minutes to fire in two more questions. First, with the Tories in so much trouble, does he think Corbyn can become prime minister? Clearly he does, and he is not just saying so to shock his own party to its senses. “I think there is a possibility that Jeremy Corbyn can win … a real possibility. Look at how close he got in terms of percentage share [in June].”

And given all that he has said so far, does he believe May is the right person to lead the Tory party into the next general election? He waits several seconds, smiles, then stands and offers his hand. “I think we’re out of time,” he says, leaving us to draw the obvious conclusion.