Kemi Badenoch has promised to “renew” the Conservative Party as she becomes the sixth person to launch a bid to become the next Tory leader.

The shadow business secretary said she would return her party to “first principles” including a focus on sovereignty and a revived confidence in capitalism.

Many see the 44-year-old as a front-runner to take over from ex-Prime Minister Rishi Sunak, regularly topping polls among Conservative Party members.

She joins Dame Priti Patel, Mel Stride, Robert Jenrick, Tom Tugendhat and James Cleverly in the race to replace Mr Sunak.

Ms Badenoch said the Conservative Party needed to focus on “doing some things well, not everything badly” to recover from their worst ever election result – which left them with 121 MPs.

Writing in The Times newspaper, she said: “My campaign is launching with an explicit focus on renewing our party for 2030 – the first full year we can be back in government and the first year of a new decade.”

Under her, the Conservatives “will speak the truth again” and return to its roots, Ms Badenoch said.

In her article, Ms Badenoch made a case for leaving the European Convention on Human Rights (ECHR), a major dividing line within the Conservative party.

Some Conservatives argue leaving the convention is key to controlling immigration and enhancing national security, but others worry it could damage the UK’s international reputation and legal protections.

“We can’t control immigration until we re-confirm our belief in the nation state and the sovereign duty it has above all else to serve its own citizens,” Ms Badenoch said.

“Our public services will never fully recover from the pandemic until we remember that government should do some things well, not everything badly.”

Central to her pledge for “renewal” and “reuniting the Conservative family” is an unwavering embracing of capitalism.

“The wealth of our nation is built upon our historic ability to capture the ingenuity and industry of our people, and the willingness of many to trade risk for reward,” she said.

“It’s become a dirty word, but our renewal must also mean a renewal for capitalism.

A committed Brexit supporter, Ms Badenoch was first elected as an MP in 2017 and used her first parliamentary speech to celebrate the Brexit vote as “the greatest ever vote of confidence in the United Kingdom”.

She gained her first major ministerial role in the Boris Johnson government, serving under then-chancellor Mr Sunak in the Treasury.

Ms Badenoch emerged as a darling of the right of her party during her time as women and equalities minister in 2021 for her stance on trans rights.

She previously ran for Conservative leader following the resignation of Boris Johnson and came fourth despite starting the race with a relatively low profile.

Ms Badenoch now regularly outperforms her rivals in approval ratings among party members, according to surveys on Conservative Home – a popular website among activists.

Before even announcing her bid, Ms Badenoch claimed she was a victim of “dirty tricks” by fellow Conservatives – passing on “dishonest” and damaging claims about her to the media.

In a social media post, Ms Badenoch said a team behind another leadership bid had sent a “dirty dossier” to journalists and spread rumours she had secretly set up a leadership campaign website.

At the same time, a story about her appeared in The Spectator magazine, claiming an online profile going by the name of “Kemi” on a Nigerian website in the mid-2000s had made a series of “direct, sometimes rude, often confrontational” comments.

The article said the statements did little to damage her forthright reputation and were unlikely to hurt her in the leadership race.

Tory MPs aiming to become the next Conservative leader must secure the backing of 10 MPs and raise £200,000 by 14:30 BST on Monday to enter the first round of voting.

Mr Sunak will remain Conservative leader until his successor is announced.

The process to choose his replacement will see Tory MPs narrow the field of candidates who secure enough backers to four by the time of the party’s annual conference in Birmingham at the end of September.

MPs will then hold a series of votes to narrow the field to a final two contenders, with party members then choosing the winner.

The online vote will end on 31 October, with the result announced two days later on 2 November, three days before the US presidential election.