Mr Jenrick said: “I think Keir Starmer has declared war on pensioners, and I’m going to fight that tooth and nail.

“Keir Starmer is making terrible political choices. He’s chosen to give a £10,000-a-year pay rise for high-earning train drivers without even settling the strikes.

“He’s chosen to give £8billion to a fantasy energy company run by Ed Miliband that doesn’t even produce any energy.

“He’s giving £10billion pounds a year to his trade union paymasters. These are the wrong choices.

“These are selfish choices which are going to hurt working people and pensioners just at the moment when their energy prices are starting to rise again.”

Mr Jenrick said as well as stripping pensioners of their winter fuel allowance, which is worth up to £300, free bus passes and the single-person council tax discount are now also under threat.

“Politics is all about choices, and you can tell a lot about someone’s politics and their values by what they spend money on and how they fund it,” he added.

“Keir Starmer is choosing to take away the winter fuel allowance from 10million pensioners, people on incomes as low as £13,000 a year, and he’s choosing to spend that money on £10,000-a-year pay rises for high-earning train drivers. I think that says a lot about who Keir Starmer is as a prime minister and as a man.”

Mr Jenrick, who quit as immigration minister in frustration after being blocked for taking tougher action to stop small boat crossings, also criticised Labour for “taking the public for fools” by rebranding illegal migration as “irregular”.

“It’s Orwellian doublespeak,” he said. “It’s outrageous that rather than solving the issue, Keir Starmer is just redefining it.

“He’s taking the British public for fools.”

Mr Jenrick said the Prime Minister has “essentially surrendered” to the people-smuggling gangs and thousands of illegal migrants who have crossed the Channel.

He believes the Conservatives can win again by being “crystal clear” about their position on immigration, which under his leadership would mean a cap on legal migration as well as leaving the European Convention on Human Rights (ECHR) to make it easier to deport people who arrive illegally.

He said: “I’ve given this a great deal of thought, and have come to the firm view that that’s not possible. There’s no process, there’s no agenda, and there’s certainly no consensus with our European allies as to how one would do that.

“At best, it would be a work of decades, but it would almost certainly end in failure like David Cameron’s attempt to renegotiate our membership of the EU. I don’t think the British public are willing to wait decades to secure our borders.

“I want to ensure that the next Conservative government solves this issue once and for all, restores our borders and keeps the public safe. So if I’m fortunate enough to lead the Conservative Party, I will ensure that our policy is to leave the ECHR and to bring order again to our borders.”

Mr Jenrick said he would not be running for the job unless he believed the party could win the next general election, but insisted he is “grounded in realism”.

“We have a mountain to climb,” he said. “The party has to be painfully honest about the mistakes we made in government. We have to listen to the public and show that we have learnt our mistakes from our mistakes.”

The father of three daughters, aged nine, 11, and 13, said Brexit was a generational project to make this country a better place for future generations but “we haven’t used the freedoms … as much as we should have done”.

“There’s so much more that we could do, and I want my party to have an inspiring vision as to how we use Brexit to drive economic growth, to deliver reduced migration and to make the country a better place,” he said.

Mr Jenrick, 42, joined the Conservative Party aged just 16 because he believed Sir Tony Blair would undo the changes that had given his working-class parents in Wolverhampton the ability to set up their own business and buy their own home.

“I feared that Tony Blair would undo all of that and would take our country backwards,” he said. “I think that’s exactly what happened. Ever since then, I’ve wanted to make the country a better place, and that’s why ultimately, I chose to go into politics, and now I’m standing to be leader of the party.

“I am a product of small-town Britain. I grew up in Wolverhampton. I represent Newark in North Nottinghamshire.

“I believe in this country. I’m fiercely patriotic, and I want to ensure that the small-c conservative values that my parents instilled in me, and I try to instil in my children, can be applied across our country.”