Rishi Sunak has warned that the world has taken open shipping lanes “for granted”, as Britain joined an international naval effort to repel Houthi rebels attacking cargo ships in the Red Sea.

The Prime Minister said that attacks on shipping by “malign actors” were “deeply concerning” and that Britain would collaborate with the United States and seven other countries to keep the shipping lane open.

Houthi rebels responded to the launch of the joint military effort, codenamed Operation Prosperity Guardian, by vowing to continue their “legitimate” attacks on cargo ships in support of Palestinians in Gaza.

Grant Shapps, the Defence Secretary, joined a US-hosted call with other defence ministers at 6am on Tuesday in which the countries agreed to put naval resources into the Red Sea to counter attacks by Houthis in Yemen.

The Navy has already sent HMS Diamond, a Type 45 destroyer, to the region and used it to shoot down a suspected Houthi drone attacking a commercial ship on Saturday.

The ship fired an Aster missile from its Sea Viper weapons system – the first time that the Navy has shot down an aerial target in 32 years.

Britain and the United States are joined on the operation by Bahrain, Canada, France, Italy, the Netherlands, Norway and the Seychelles.

France already has a naval presence in the area, while Italy has said that it was sending the frigate Virginio Fasan. Spain has said that it could join the operation, subject to “the decisions of the European Union and Nato”.

Defence sources said that HMS Lancaster, a Type 23 frigate, was stationed in the Gulf and could join the operation at a later date to provide additional naval support.

The announcement of a Western-led naval coalition came after several shipping companies said that they would bypass the Bab el-Mandeb Strait in the Red Sea and instead sail the long way around Africa – a route that takes an additional three weeks.

The oil giant BP has said that it will pause all shipments through the Red Sea, prompting concerns about the global oil price in the week before Christmas.

Four of the world’s biggest shipping companies – CMA CGM Group, Hapag-Lloyd, Maersk and MSC – have diverted their vessels.

Denmark’s Maersk said on Tuesday that “all vessels previously paused and due to sail through the region will now be rerouted around Africa via the Cape of Good Hope”.

The route is also used by tankers carrying much of Britain’s supply of liquified natural gas, including supplies from Qatar, which accounted for 30 per cent of Britain’s gas imports last year.

The route through the Bab el-Mandeb Strait is used for about 10 per cent of the world’s shipping, with 23,000 ships passing through it each year.

Houthi rebels based in Yemen, which has been in a state of civil war since 2014, have also fired missiles directly at Israel, across a distance of more than 1,000 miles.

The group is funded by Iran and is thought to have been used as a proxy, alongside Hamas, for Iran’s conflict with Israel.

Mr Shapps said: “These illegal attacks are an unacceptable threat to the global economy, undermining regional security and are threatening to drive up fuel prices.

“This is an international problem that requires an international solution. That is why HMS Diamond has joined Operation Prosperity Guardian.

“This new task force will protect shipping and vital trade routes in the Red Sea, where large amounts of goods and oil transit through to Europe and on to the UK.”

HMS Diamond, which began service in 2011, is equipped with a Wildcat helicopter that can be fitted with a machine gun, torpedoes and missiles.

Commander Pete Evans, the ship’s commanding officer, said: “The Royal Navy has always been committed to the protection of maritime trade and ensuring that both people and shipping remain safe in international waters.

“HMS Diamond and her ship’s company stand ready to work alongside our allies to protect peace and security.”

On Monday night, Lloyd Austin, the US defence secretary, said that the escalation of attacks by Houthis in the Red Sea “threatens the free flow of commerce, endangers innocent mariners and violates international law”.

Speaking at the liaison committee in Parliament on Tuesday, Mr Sunak added that Britain had “always believed very strongly in free and open shipping lanes” but “that is now being threatened by malign actors”.

“It’s just further evidence that the international picture is both complex and more challenging and previously we, I think, may have taken many of these things for granted,” he said.

“It’s clear that we can’t and we need to invest in our defence capability and strengthen our alliances to keep everyone at home safe and protect our economy, too.”

However, Mohammed Abdel-Salam, the Houthis’ chief negotiator and spokesman, said that the Iranian-backed group would continue attacks on the shipping lanes in support of Hamas.

“The American-formed coalition is to protect Israel and militarise the sea without any justification, and will not stop Yemen from continuing its legitimate operations in support of Gaza,” he wrote on X, formerly known as Twitter.