Sir Keir Starmer must “urgently” review the UK’s intelligence sharing arrangements with the US following a “reckless” national security leak.

Donald Trump’s national security officials, including the defence secretary and national security adviser, texted plans for an attack on Yemen to a group chat that had accidentally included a journalist.

Downing Street on Tuesday said it was confident that any UK intelligence shared with the US was being handled appropriately despite the breach.

But Sir Ed Davey, leader of the Liberal Democrats, called for a review of the UK’s intelligence-sharing arrangements with the US.

He said Trump's administration “can’t be trusted to take even the most basic steps to keep its own intelligence safe”.

Sir Ed added: “Their fly-by-the-seat-of-your-pants approach to security means it could only be a matter of time until our own intelligence shared with them is also leaked. This could put British lives at risk.”

The US carried out a series of air strikes against the rebel Houthi militant group in Yemen on March 15 following continued attacks on shipping in the Red Sea – an operation in which the UK provided air-to-air refuelling support.

But two hours beforehand, details of the attack had been sent to a Signal group chat that included the US vice-president JD Vance, defence secretary Pete Hegseth and secretary of state Marco Rubio and national security adviser Mike Walz.

Signal chats are encrypted, but are not approved by the US government for discussion of classified material.

The use of the app to provide details of the airstrikes came to light because one participant had accidentally added the editor-in-chief of The Atlantic magazine, Jeffrey Goldberg, to the group.

Deputy Prime Minister Angela Rayner dismissed talk of reviewing intelligence-sharing arrangements.

She said: “We’ve been sharing intelligence and information for many decades and continue to do that through our secure networks.

“It’s for the US and US president and government to explain and decide what they are doing in regards with security and that Signal group and how they have seen that.”

The US National Security Council said it was investigating how Mr Goldberg came to be included.

Former national security adviser Sir Mark Lyall Grant said: “In modern government now, a lot of communication is done through social media and messaging apps but nonetheless, this level of defence and security intelligence discussion clearly shouldn’t be happening on any unmanaged messaging app, and certainly not on things like Signal.”

“Signal is more secure than Whatsapp or text messaging but nonetheless of course, can be intercepted, and violated by foreign agents so it shouldn’t be used for this level [of intelligence].”

Democratic senator Mark Warner slammed the “sloppy, careless, incompetent” handling of classified information.

While speaking before the US senate intelligence committee, he called for the entire chat to be released.

But Mr Trump backed Mr Walz, dismissing his accidental leaking of top secret war plans to a journalist as a “glitch”.

The president’s national security adviser faced calls to resign after he erroneously added the editor-in-chief of the Atlantic magazine.

Standing by Mr Walz, the US President said: “Michael Waltz has learnt a lesson, and he’s a good man.”

He described the leak as “the only glitch in two months, and it turned out not to be a serious one.”

Mr Trump said Mr Goldberg’s presence in the chat had “no impact at all” on the military operation.

Asked how the journalist had been added to the chat, Mr Trump said: “It was one of Michael’s people on the phone. A staffer had his number on there.

Armed forces minister Luke Pollard told the Commons Defence Committee that no British service personnel had been put at risk because of the blunder.

He added: “All UK service personnel are covered by our normal approach to operational security, and the committee will understand that I won’t go into the details of how we keep our involvement in any support for military operations in the Red Sea or anywhere else (secure).

“But we’ve got high confidence that the measures that we have got with our allies, including the United States, remain intact.”