Britain joined the US in unleashing targeted strikes against military facilities in Yemen last night in response to "reckless actions" of Houthi rebels in the region.
Action was taken after weeks of disruption to international shipping in the Red Sea.
The rebels had launched a series of attacks on shipping routes in the Red Sea, which they claimed to be a show of support for Palestine and terror group Hamas.
Houthi officials have reacted with fury to the UK and US' response, calling the strikes "barbaric".
The US Air Force said American and British forces struck more than 60 targets in 16 locations.
In a chilling threat of further retaliation, high-ranking Houthi official Ali al-Qahoum added: "The battle will be bigger…. and beyond the imagination and expectation of the Americans and the British."
The Cabinet was informed of the plans in a meeting called last night by No10. In an unusual move, the Government also briefed Sir Keir Starmer and shadow defence secretary John Healey.
In a statement released after the bombings, Prime Minister Rishi Sunak said: "In recent months, the Houthi militia have carried out a series of dangerous and destabilising attacks against commercial shipping in the Red Sea, threatening UK and other international ships, causing major disruption to a vital trade route and driving up commodity prices.
"Their reckless actions are risking lives at sea and exacerbating the humanitarian crisis in Yemen.
"Despite the repeated warnings from the international community, the Houthis have continued to carry out attacks in the Red Sea, including against UK and US warships just this week. This cannot stand. The United Kingdom will always stand up for freedom of navigation and the free flow of trade.
"We have therefore taken limited, necessary and proportionate action in self-defence, alongside the United States with non-operational support from the Netherlands, Canada and Bahrain against targets tied to these attacks, to degrade Houthi military capabilities and protect global shipping.
"The Royal Navy continues to patrol the Red Sea as part of the multinational Operation Prosperity Guardian to deter further Houthi aggression, and we urge them to cease their attacks and take steps to de-escalate."
US President Joe Biden added: “These strikes are in direct response to unprecedented Houthi attacks against international maritime vessels in the Red Sea – including the use of anti-ship ballistic missiles for the first time in history.
“These attacks have endangered US personnel, civilian mariners, and our partners, jeopardised trade, and threatened freedom of navigation.
“More than 50 nations have been affected in 27 attacks on international commercial shipping. Crews from more than 20 countries have been threatened or taken hostage in acts of piracy.
“More than 2,000 ships have been forced to divert thousands of miles to avoid the Red Sea — which can cause weeks of delays in product shipping times. And on January 9, Houthis launched their largest attack to date—directly targeting American ships.”