Penny Mordaunt, the Leader of the House of Commons, engaged in a heated exchange with Labour deputy leader Angela Rayner during a BBC debate. Mordaunt criticized Rayner's stance on Britain's nuclear deterrents, arguing that it would jeopardize the country's safety. She suggested that Russian President Vladimir Putin would not believe Britain's commitment to using its nuclear deterrent if Labour were to win the election.

Mordaunt pointed out that Rayner had voted against renewing the Trident submarines in 2016 under Jeremy Corbyn's leadership, but now claims to support them. "Imagine what Putin is thinking," Mordaunt stated. "Without credibility, we become a target. If we become a target, you are less safe. It’s too late for this generation of Labour politicians, that credibility is shot. Do not vote these people in."

Rayner countered by accusing the Conservative Party of cutting the armed forces, crashing the economy, and leaving the country in a "real mess." She insisted that both she and Labour leader Keir Starmer are committed to maintaining the nuclear deterrent and investing in it.

Mordaunt maintained that a deterrent is ineffective if an adversary does not believe it will be used. Rayner, however, retorted that the Conservative Party has made Britain a "laughing stock internationally" and that she, having a brother who served in Iraq, would not be lectured on her commitment to national defense.

When Rayner criticized Mordaunt for supporting Liz Truss, who she claimed "crashed our economy," Mordaunt defended Truss, stating that even at her worst, Truss recognized the need for a nuclear deterrent. Rayner dismissed this as a lie.

During the debate, Mordaunt also acknowledged that Rishi Sunak's decision to leave the D-Day commemorations early was "completely wrong" and that his apology to veterans and the public was appropriate. A viewer poll conducted after the debate indicated that viewers were more likely to see Mordaunt as a better Prime Minister than Sunak, although a majority remained undecided.