Keir Starmer slapped down Tory leader Kemi Badenoch and claimed she was not “fit to be prime minister” during a brutal PMQs exchange today.

Badenoch began by repeating reports that Labour’s plan to give the Chagos islands to Mauritius would cost £18bn – twice the original sum.

The PM has allegedly made concessions to Mauritius over the British overseas territory – which is also home to a UK-US naval base – sparking a row in Westminster this week.

Badenoch claimed the reported move from Starmer “is an immoral surrender so North London lawyers can boast at their dinner parties.”

But the PM replied: “This is a military base vital to our national security. A number of years ago, the legal certainty of that base was thrown into doubt.

“I’ll pick my words carefully – without legal certainty the base cannot operate as it should, which is bad for our national security and its a gift to our adversaries.

“Some in the party opposite know exactly what I’m talking about, that’s why their government started negotiations about our sovereignty.”

“They were right to do so,” the prime minster said, before pointing out that the Tories hosted 11 of the 13 rounds of negotiations.

He then rounded on Badenoch personally, saying: “If the leader of the opposition is properly briefed on the national security implications when she’s asking these questions – which she’s perfectly entitled to do – then she knows exactly what I’m talking about.”

However, Starmer claimed if she was not aware of what issues he was talking about, she was “not doing her job, she’s not concerned about national security and she’s not fit to be prime minister!”

A huge cheer went from the Labour benches at that.

Badenoch claimed Starmer “bends the knee to anyone who asks him” and accused him of a “weak and waffle-y” answer before trying to move onto questions about the Rosebank oil field.

But the PM did not let it slide, and instead hit back: “I notice she did not say she was briefed.”

He pointed out that he had offered to give Badenoch a briefing on any national security issue when she became the leader of the opposition.

“She’s more interested in chasing Reform than she is national security,” the PM said.

“She doesn’t even what to know what is going on otherwise she would have asked for the relevant briefing.”

He added: “Yet again all she’s proving all she can do is student politics, and plain party politick.”