Speaking to the BBC, Ms Mordaunt insisted she was "in it to win it" and wasn't "contemplating how the other camps are organising themselves".

The Commons leader avoided detailing her approach to public spending.

However, she said it was "critical" to rebuild stability.

Ms Mordaunt was the first MP to declared her intention to run in the race to replace Liz Truss as Conservative leader and prime minister.

However, only 24 MPs have publicly come out to support her - and she needs 100 by 14:00 BST on Monday to remain in the contest.

The MP for Portsmouth North is currently lagging behind former chancellor Rishi Sunak who, according to the BBC's tally, has 146 backers and Mr Johnson, who has yet to officially declare, on 57.

Later on Sunday, her supporters dismissed the idea of her backing Mr Johnson in the leadership contest.

Amid claims Mr Johnson asked her to drop out and support him earlier on Sunday, a former minister backing Ms Mordaunt said: "Penny has huge admiration for Boris's achievements but she doesn't see how he can in any way bring the stability we now urgently need".

Appearing earlier on BBC One's Sunday with Laura Kuenssberg programme, Ms Mordaunt was asked about her relative lack of support.

She replied she was "very confident" about her progress, and pointed out that during the last leadership contest in the summer, she secured endorsements from 105 MPs, before being knocked out by Ms Truss and Mr Sunak. She said many of those MPs were returning to support her again.

She was then asked about her time in government with Ms Truss, and said that the prime minister - who announced her resignation on Thursday - had been "right to focus on growth".

But Ms Mordaunt said that she personally regretted the mini-Budget, which triggered economic turmoil. She said it was now "absolutely critical" to rebuild stability, and repeated her pledge to keep Jeremy Hunt on as chancellor.

Mr Hunt, who has warned of tax rises and spending cuts, is due to give a statement on the economy on 31 October.

Ms Mordaunt said that if she became prime minister the statement would go ahead - but refused to be drawn on the details of that package.

On possible cuts to the health service, she said the government would have to make "efficiency savings" but added that she would protect the "services people need".

She said that during the first leadership campaign she had recognised the need to support people through "a very difficult winter" in ways that would not exacerbate inflation such as "targeted and measured tax cuts".

Appearing on the same programme, former foreign secretary Dominic Raab - who is backing Rishi Sunak - was asked if a deal had been reached between his chosen candidate and Mr Johnson.

He replied: "I don't think there's any issues around deals here and that's not the right way to proceed."

He added: "What they did have was a very good conversation about the need for unity."