In a speech to the leadership, he cleverly accuses Starmer of “vandalism” in defence spending

In a speech billed as the most important part of his election campaign, the former home secretary said his priorities as prime minister would be to strengthen national security, reduce migration and restore “faith in capitalism”.

He promised to spend three percent of GDP on defence if elected prime minister, but accused Sir Keir of recklessness for abandoning the previous government's timetable of spending 2.5 percent.

He said: “Starmer has destroyed this in an act of vandalism.

“Peace is not achieved through greed and malice. Security is achieved through strength. By preparing for the worst rather than hoping for the best.

“We will send a signal to our enemies that the British are ready. We will not leave the field.”

Mr Cleverly added that the UK currently spends “ten times” more on health, social care and pensions than on defence.

He added: “Starmer says we cannot afford to spend more on defence. I say we cannot afford not to.”

The attacks on the Prime Minister continued, with Mr Cleverly insisting that only a united Conservative Party would be taken seriously by a public that he believed was rapidly losing faith in the Labour Party.

He said: “We must unite if we want the British people to listen to us again. When they get fed up – and they inevitably will – with Starmer's inept, high-taxing, bureaucratic, big-government and cronyist government, they will look to us again for the change they want for the country.”

Mr Cleverly said his changes to visa programs would now “cut migration by half”, adding that during his time as Home Secretary “the number of asylum applications has fallen, the backlog has been reduced and the approval rate and number of deportations have fallen”.

He added that as prime minister he would use his “contacts and reputation” to “revitalize” the partnership with Rwanda as a deterrent to illegal immigration.

Mr Cleverly accused Labour of an “arrogant and callous disregard for diplomatic niceties that bind the world” and claimed the Government had informed the media that the plan was being abandoned before informing the Rwandan Government.

As a third priority, Mr Cleverly stated: “We must address the crisis of confidence in capitalism.”

He added: “We need to unleash real growth again and show young people that free markets, not planned economies, are their friends.”

“We need to make them capitalists. Too many people believe that high taxes will help them instead of keeping them small.”

“They believe that more regulation will protect them rather than benefit incumbent providers.

“Protectionism raises their costs, limits their choices, benefits the already rich and harms the emerging poor.

“I will make promoting our economic growth a central mission of our party.”

Mr Cleverly also promised to abolish stamp duty and cut the welfare budget, while saying he would be “honest about the trade-offs”.

He said: “We should enable self-reliance, putting families first, resilience and community-based solutions.

“Taxes and subsidies can no longer be our mantra, so we must start thinking and acting like conservatives again.”

The field of six candidates – which also includes Kemi Badenoch, Robert Jenrick, Dame Priti Patel, Tom Tugendhat and Mel Stride – will be reduced to four by the time of the Conservative conference at the end of the month.

MPs will then hold further rounds of voting to select two final candidates for Conservative members to choose between, with the result announced on 2 November.