James Cleverly and Robert Jenrick will face a grilling from Conservative members on the main stage of the party conference during its penultimate day.
The two hopefuls to succeed Rishi Sunak will follow in the footsteps of rivals Kemi Badenoch and Tom Tugendhat, who were questioned by members on Monday.
The Birmingham conference, a subdued affair in which Tory members are seeking to regroup after their crippling election defeat, was overshadowed by global events as it headed into its third day.
Israel began a military incursion into Lebanon on Monday night, sparking the UK Government to warn British nationals in Lebanon to leave amid concerns about the widening conflict.
On Monday, Ms Badenoch and her campaign team continued to grapple with the aftermath of her suggestion that statutory maternity leave pay was part of an “excessive” function of tax.
Speaking on the main conference stage, she compared her remarks with the often-repeated quote attributed to Margaret Thatcher that there is “no such thing as society”, from an interview the ex-prime minister gave to a women’s magazine about the importance of family.
Ms Badenoch said: “That very good explanation got cut down into a soundbite that was used to attack her.
“When you are a leader, when you are a Conservative, when you are making the argument for conservative principles, your opponents are going to try and turn it into something else.”
Ms Badenoch then appeared to suggest policies like the minimum wage and maternity leave pay were burdensome for many businesses.
The North West Essex MP said: “There’s a cafe in my constituency that closed down and the lady who owned it said, ‘I can’t afford to pay the wages any more. I can’t afford minimum wage. I can’t afford for my staff to go on maternity’.
“We are overburdening businesses. We are overburdening them with regulation, with tax. People aren’t starting businesses any more because they’re too scared.”
Former security minister Mr Tugendhat used his main stage appearance to apologise for infighting between Conservative MPs and failings by the central party during the previous government.
“They all let you down. I’m sorry,” he told activists.
Mr Jenrick and his team faced questions about the source of a £75,000 donation to his campaign.
Entrepreneur Phillip Ullmann said he gave the money to the Newark MP through Spott Fitness, a fitness coaching app provider which he said is “part of my family’s group of businesses”.
The UK elections watchdog said it is “considering carefully” a letter from Labour demanding an investigation into the source of the money after Mr Jenrick received three donations of £25,000 from the business in July.
On the conference fringe, former home secretary Mr Cleverly said the phrase “stop the boats” was an error, adding: “It distilled a very, very complicated and challenging problem into a soundbite,” when asked about his record on tackling the migration crisis.
Analysis by polling company Ipsos suggested voters who deserted the Tories at the general election did so for a host of reasons.
To win them back, the party would need to “convince quite different groups of voters the party shares their values”, Ipsos director of politics Keiran Pedley said.
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