Kemi Badenoch has said she will not be rushed into announcing policies as she dismissed the 'easy answers' offered by Nigel Farage.
The Tory leader insisted there was 'no quick fix' to regain voters' trust after her party was kicked out of office for failing to deliver on its promises.
Rebuilding the Conservatives was a 'marathon not a sprint', she added in an interview with Radio 4's Today programme broadcast yesterday.
Meanwhile, a petition to call a new general election, over anger at the Labour government, last night passed three million signatures. It will be debated in Parliament on January 6.
In her interview, Mrs Badenoch also admitted that upcoming local elections would be 'very difficult' and she did not have enough time for her project, which she believes will take longer than the life of one parliament.
But she dismissed fears among some in the party that the 'vacuum' means it will be overtaken in the polls, and membership numbers, by Right-wing rival Reform.
Mrs Badenoch said: 'Reform is saying stuff because it hasn't thought it all through. You can give easy answers if you haven't thought it all through.
'I do the thinking and what people are going to get with new leadership under me is thoughtful Conservatism, not knee-jerk announcements.
She said Reform leader Mr Farage can make announcements because he 'doesn't care' about the views of other people in his party.
'I care. I am a custodian of something very special,' she said.
Mrs Badenoch added that when the Tories lost power in 1997 they decided to 'rush out' with a long list of policies – but it did not work and took the party 13 years to win another general election.
Referring to July's defeat, the ex Cabinet Minister said: 'The public did not kick us out because they didn't like our manifesto. They kicked us out because they did not trust us, because we did not deliver.
'We need to explain why we didn't deliver. We need to re-earn that trust.'
Asked if she had as much time as she thinks to neutralise the threat posed by Mr Farage, she admitted: 'Four years even in my view is not enough time to do what we want to do, which is a revolution in terms of how the state works and how our society functions.'
With council elections due in May, Mrs Badenoch pointed out the last time they were fought was 2021 – when Boris Johnson benefited from a Covid vaccine bounce.
She warned: 'It's not going to be like that.
'And I think what many commentators need to understand is that this is a marathon, not a sprint.'
A Labour Party spokesman said Mrs Badenoch 'has no solutions'.